how do you know when to use tenotomy hamstring lengthening 27392 vs 27395? in the ortho coding companion book it says the difference is length of incsion and method ('coding tips'.)

yet in the same book the decription of both procedures has a 7-10 cm incision. this has made it very confusing for me. what else should i look for to differentiate the 2 codes and pick the correct one? i want to use the 27395. am i correct?

i know it's hard w/o op-report but it's a few pages.