Illegal pitch - ASA Mens FP

[Andy]

I was asked to work an ASA mens FP league last night. I know the pitching rules for men are different in that they are allowed to take the "rocker" step backward similar to FED. Here is my dilema:

It was a two game set and I was the BU for the second game. Both pitchers were dragging their pivot foot back along the pitchers plate as they took the step backward. The pivot foot did not lose contact with the plate. As they would start their forward motion, there were times when the pivot foot would be lifted completely off the plate and set back down on the plate before the pitch was delivered. I did not call any illegal pitches in that game. After the game I talked to two guys that were working the other field, they both said to call that - the reasoning being that the rules already allow them the rocking motion and allowing that foot to come off the pitchers plate just added to the rocking motion.

I haven't done mens FP for several years and just wasn't sure of the correct ruling. Looking forward to what all of you have to say.