I think Vittorio has it somewhere in his post about cutting off the back of X10s. He does it apparently.. Maybe you can find an answer in his postings
No, I don't remember any of my posts with such content.
Anyhow, cutting X10 on the back was quite common for compound shooters to get the right (stiffer) spine from their shafts, usually from 410 and 450 basic spines.
Then, Easton has introduced Pro Tour shafts, that are a kind of "pre-cutted" X10, and so I have to suppose that compound shooters now can avoid any ... cutting activity

From the technical point of view, shafts shot from a compound bow withstand the maximum poundage on the second half of their lenght, so the spine of the second half is dominating for grouping consistency . If this part is made stiffer, the entire front part tend to react like it was the point, generating an effect that is similar to an improved dynamic FOC for the arrow.
So, during release, arrow cleans the bow like a very short arrow with a very heavy point, adding to this the fact that a stiff second half has less oscillations on the horizontal plan. Benfits are immediately evident by any way of tuning...