Because our DOM is about 3 times my size, and he says so....
Seriously though, he's got a lot of experience with these things, and has worked all over the place on them, and if he says the straps get beat up, I believe him. Now, I don't know anyone who flies the 500 that doesn't flip the pedals - until now I guess. As I said, I've been told it's good housekeeping to do so. I used the word "must" because I've never encountered anyone who leaves them at full deflection. If that works for you and others, who am I to question it. By all means, continue on.
Factual basis for anything is of course required, but remember those facts can come from many sources. I don't fix'em, I fly em - but I do listen to those who fix for a living.
RH