HELP! Armature from edge loops

hi,
I’m having trouble with this code:


#########################################
## huesos desde edge loops / geometria ##
#########################################


bl_info = {
    "name": "Armature from Mesh",
    "version": (0, 1, 4),
    "blender": (2, 6, 9),
    "location": "View3D > Tool Shelf",
    "description": "Grows a chain of bones from edge loops in geometry",
    "category": "Object"}


import bpy, mathutils
from mathutils import Vector
from bpy.props import BoolProperty, FloatProperty, IntProperty, StringProperty


# centroide de una seleccion de vertices
def centro(ver):
    vvv = [v for v in ver if v.select]
    if not vvv or len(vvv) == len(ver): return ('error')
    x = sum([round(v.co[0],4) for v in vvv]) / len(vvv)
    y = sum([round(v.co[1],4) for v in vvv]) / len(vvv)
    z = sum([round(v.co[2],4) for v in vvv]) / len(vvv)
    return (x,y,z)


# recuperar el estado original del objeto
def volver(obj, copia, om, msm, msv):
    for i in copia: obj.data.vertices[i].select = True
    bpy.context.tool_settings.mesh_select_mode = msm
    for i in range(len(msv)):
        obj.modifiers[i].show_viewport = msv[i]


class BB(bpy.types.Operator):
    bl_idname = 'object.mesh2bones'
    bl_label = 'Create Armature'
    bl_description = 'Create an armature rig based on mesh selection'
    bl_options = {'REGISTER', 'UNDO'}


    numb = IntProperty(name='Max Bones', min=1, max=1000, soft_max=100, default=5, description='Max number of bones')
    skip = IntProperty(name='Skip Loops', min=0, max=5, default=0, description='Skip some edges to get longer bones')
    long = FloatProperty(name='Min Length', min=0.01, max=5, default=0.15, description='Discard bones shorter than this value')
    ika = BoolProperty(name='IK constraints', default=True, description='Add IK constraint and Empty as target')
    rotk = BoolProperty(name='IK Rotation', default=False, description='IK constraint follows target rotation')
    auto = BoolProperty(name='Auto weight', default=True, description='Auto weight and assign vertices')
    env = BoolProperty(name='Envelopes', default=False, description='Use envelopes instead of weights')
    rad = FloatProperty(name='Radius', min=0.01, max=5, default=0.25, description='Envelope deform radius')
    nam = StringProperty(name='', default='hueso', description='Default name for bones / groups')


    @classmethod
    def poll(cls, context):
        obj = bpy.context.object
        return (obj and obj.type == 'MESH')


    def draw(self, context):
        layout = self.layout
        column = layout.column(align=True)
        column.prop(self,'numb')
        column.prop(self,'skip')
        column.prop(self,'long')
        column = layout.column(align=True)
        column.prop(self,'auto')
        if self.auto:
            column.prop(self,'env')
            if self.env: column.prop(self,'rad')
        column.prop(self,'ika')
        if self.ika: column.prop(self,'rotk')
        layout.prop(self,'nam')


    def execute(self, context):
        scn = bpy.context.scene
        obj = bpy.context.object
        fac = obj.data.polygons
        # guardar estado y seleccion
        ver, om = obj.data.vertices, obj.mode
        msm, msv = list(bpy.context.tool_settings.mesh_select_mode), []
        for i in range(len(obj.modifiers)):
            msv.append(obj.modifiers[i].show_viewport)
            obj.modifiers[i].show_viewport = False
        bpy.ops.object.mode_set(mode='OBJECT')
        copia = [v.index for v in ver if v.select]
        sel = [f.index for f in fac if f.select]
        bpy.ops.object.mode_set(mode='EDIT')
        bpy.context.tool_settings.mesh_select_mode = [True, False, False]
        bpy.ops.mesh.select_all(action='DESELECT')
        txt = 'Select a face or a vertex where the chain should end...'
        bpy.ops.object.mode_set(mode='OBJECT')


        # crear rig unico -desde vertice/s y no desde caras-
        if sel == []:
            sel = ['simple']
            for i in copia:
                obj.data.vertices[i].select = True


        # reciclar el rig en cada refresco...
        try: scn.objects.unlink(rig)
        except: pass


        # loop de caras
        for i in sel:
            if sel[0] != 'simple':
                for v in ver: v.select = False
                for v in fac[i].vertices: ver[v].select = True
            lista = [centro(ver)]
            if lista[0] == 'error':
                self.report({'INFO'}, txt)
                volver(obj, copia, om, msm, msv)
                return{'FINISHED'}


            # crear lista de coordenadas para los huesos
            scn.objects.active = obj
            for t in range(self.numb):
                bpy.ops.object.mode_set(mode='EDIT')
                bpy.ops.object.vertex_group_assign_new()
                for m in range(self.skip+1):
                    bpy.ops.mesh.select_more()
                bpy.ops.object.vertex_group_deselect()
                bpy.ops.object.mode_set(mode='OBJECT')
                lista.append(centro(ver))
                bpy.ops.object.mode_set(mode='EDIT')
                bpy.ops.object.vertex_group_select()
                bpy.ops.object.vertex_group_remove()
                if lista[-1] == 'error':
                    self.numb = t
                    lista.pop()
                    break
                if len(lista) > 1:
                    delta = Vector(lista[-2]) - Vector(lista[-1])
                    if delta.length < self.long:
                        lista.pop()


            bpy.ops.mesh.select_all(action='DESELECT')
            bpy.ops.object.mode_set(mode='OBJECT')


            # crear armature y copiar transformaciones del objeto
            lista.reverse()
            if len(lista) < 2:
                self.report({'INFO'}, txt)
                volver(obj, copia, om, msm, msv)
                return{'FINISHED'}
            try: arm
            except:
                arm = bpy.data.armatures.new('arm')
                if self.env: arm.draw_type = 'ENVELOPE'
                else: arm.draw_type = 'STICK'
                rig = bpy.data.objects.new(obj.name+'_rig', arm)
                rig.matrix_world = obj.matrix_world
                if self.env: rig.draw_type = 'WIRE'
                rig.show_x_ray = True
                scn.objects.link(rig)
            scn.objects.active = rig
            bpy.ops.object.mode_set(mode='EDIT')


            # crear la cadena de huesos desde la lista
            for i in range(len(lista)-1):
                bon = arm.edit_bones.new(self.nam+'.000')
                bon.use_connect = True
                bon.tail = lista[i+1]
                bon.head = lista[i]
                if self.auto and self.env:
                    bon.tail_radius = self.rad
                    bon.head_radius = self.rad
                if i: bon.parent = padre
                padre = bon
            bpy.ops.object.mode_set(mode='OBJECT')


            # crear IK constraint y un Empty como target
            if self.ika:
                ik = rig.data.bones[-1].name
                loc = rig.matrix_world * Vector(lista[-1])
                rot = rig.matrix_world * rig.data.bones[-1].matrix_local
                bpy.ops.object.add(type='EMPTY', location=loc, rotation=rot.to_euler())
                tgt = bpy.context.object
                tgt.name = obj.name+'_target.000'
                if len(sel) > 1:
                    try: mega
                    except:
                        bpy.ops.object.add(type='EMPTY', location = obj.location)
                        mega = bpy.context.object
                        mega.name = obj.name+'_Controls'
                        tgt.select = True
                    scn.objects.active = mega
                    bpy.ops.object.parent_set(type='OBJECT')


                scn.objects.active = rig
                bpy.ops.object.mode_set(mode='POSE')
                con = rig.pose.bones[ik].constraints.new('IK')
                con.target = tgt
                if self.rotk: con.use_rotation = True
                tgt.select = False
                bpy.ops.object.mode_set(mode='OBJECT')


        obj.select = True
        if self.auto:
            if self.env: bpy.ops.object.parent_set(type='ARMATURE_ENVELOPE')
            else: bpy.ops.object.parent_set(type='ARMATURE_AUTO')
        scn.objects.active = obj
        volver(obj, copia, om, msm, msv)
        return{'FINISHED'}


class IGU(bpy.types.Panel):
    bl_label = 'Bones from mesh'
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'TOOLS'


    def draw(self, context):
        layout = self.layout
        layout.operator('object.mesh2bones')


def register():
    bpy.utils.register_class(BB)
    bpy.utils.register_class(IGU)


def unregister():
    bpy.utils.unregister_class(BB)
    bpy.utils.unregister_class(IGU)


if __name__ == '__main__':
    register()

I use this code in mesh extra tools in contrib to create armature along extrusions.
Something changed in Blender that now the armature length does not match edge loops.
Can anyone help solve?

Old Behavior:

New Behavior:


As you can see there’s a big difference here.

I want to fix this addon in contrib as it’s a handy rigging tool.
I know the skin modifier does similar, but not as quick & easy as this script & certainlty the script is more useful on large mesh such as this:

& the addition of the Empty as control is very useful.

Thanks for any help.