How to add +/-10 offset to animated left/right/up/down slider values?

I bought this $3 addon from a creator:

https://superhivemarket.com/products/accurate-region-border

How you use the addon: You use the slider to manipulate the values or manually enter a number value and then press “I” on the keyboard to key it (there’s no autokey feature).

Addon:

r/blenderhelp - Blender Scripting Help: Add +/-10 offset to animated left/right/up/down slider values for all keyframes?|544xauto

How I’ve been using the addon: I’ve been manually typing +/-10 for each slide and for each key/keyframe in the timeline.

r/blenderhelp - Blender Scripting Help: Add +/-10 offset to animated left/right/up/down slider values for all keyframes?|750xauto

Feature request: Is there a way to add to the existing addon script I bought it so it subtracts/ adds 10 to whatever value I animate for the left, right, up, down value. For example, it will subtracts 10 for the left slider value, add 10 for the right slider value, adds 10 for the up slider value and subtracts 10 for the down slider value from whatever the number value is?

For example, keyframe one’s values are: left 192, right 1722, up 788 and down 210 so it should subtracts 10 for the left slider value, add 10 for the right slider value, adds 10 for the up slider value and subtracts 10 for the down slider value from whatever the number value was meaning the new values are left 182, right 1732, up 798 and down 200.

It should do the same thing for each key/ keyframe meaning if keyframe eight’s values are left 514, right 1498, up 978 and down 240 so it should subtracts 10 for the left slider value, add 10 for the right slider value, adds 10 for the up slider value and subtracts 10 for the down slider value from whatever the number value was meaning the new values are left 504, right 1508, up 988 and down 230.

The script should repeat itself for every left, right, up and down slider value for every key/keyframe keyed in the timeline (subtracts 10 for the left slider value, add 10 for the right slider value, adds 10 for the up slider value and subtracts 10 for the down slider value from whatever the number value is).

If it’s possible and you can help code and script please let me know. I got permission from the addon creator to show/send the addon file.

I reached out to another addon creator who knows how to code and write scripts and they said to add this feature request onto an existing addon it would cost me > 100 Euro to do and as a Blender Hobbyist who have not yet earned any money from Blender projects it’s out of my budget. That’s over >$115 for a $3 addon I purchase but I want to add this feature. So if there’s any addon creators, people who know how to script and code and can help me with my feature request please reach out because I don’t know how to script and write code.

Thank you to everyone who has reach out. The position is filled and I found a addon developer for the job.