Ok, I should have put this image up here to begin with but wasn't sure if I even had it. Each scute only gets one notch, and each scute corresponds with only one value. Individual 1 would only be marked on one scute, while individual 37 would have 3 scutes marked (10, 20 and 7).
What I had envisioned for my form layout was to include this image with a checkbox next to each scute that has a value, and by clicking on that box you would "activate" that value. The individual ID field would then add up each activated value.
Hopefully I've included all the information needed this time! Sorry for any confusion, and thanks for the help.
Oh, and, yes theoretically each person notching turtles would use the convention in the image to do so. Deviating from that and replicating the same code would create problems, although multiples of the same ID number would be ok if seperate turtles species started at individual 1 (i.e., species X individual 1 would be acceptable).