Random Vexing Scripting Question

Miss Animated

Ok- I hope I can articulate this correctly regarding animations.  I am looking to see if there is a script out there that can take existing node values (any node, any figure, any object) and add an offset value that would apply to the frame, range, or entire animation?

What's annoying is when I get an animation to sort of fly, but the neck bend needs to increase by 15 or decrease by 15.  currently, I have to go to EVERY INDIVIDUAL FRAME and add/subtract the offset I need.  That's great, if I'm not doing this more than 50 frames!

Does that make sense?  If the values of a bend node are 5.2, 6,2, 7,3, 8.5 and 10.1, I would like a script that could maintain the transition, but at a lesser bend (say 6) so the values would come out -0.8, 0.2, 1.3, 2.5 and 4.1...and so forth for larger frames, other nodes, etc.

Anything like that out there?  I've got limited python experience, but I can never find the correct path to the container where the individual values are stored...

Thanks!