No need of the whole model you’re working on, you should just delete all that is not needed to reproduce the problem.
This way it can be reported and hopefully fixed, because i tried to reproduce your case in 2.71 , even adding a subsurf too as i remember in the past there were some problem with knife and subsurf that were supposed to be solved :
In ortho mode :
And it seems to cut correctly
Then i did an undo and tried the same in perspective mode :
Still cutting correctly :
So there must be something related to the topology of that specific model, some edge angle or something else i just can’t reproduce on my own by eyeballing, what is needed is that part of your model (again, no need of the complete model, just the part in screenshot to reproduce your case) to get this fixed.
Because i agree, the knife is a very important tool, after 2 years of the bmesh new knife having been introduced, we should expect it to cut correctly when we use it, especially on very simple user case like that.