Ruling on release point

[fullor30]

1st year softball ump, strictly rec league stuff and I have alot to learn. I was doing a coed 14" mush ball game and pitcher would move to far end of rubber, stretch legs out as far as possible all the while maintaining contact with rubber and release having a side arm effect. Batter complained calling it illegal.

I said you may very well be correct, as I don't know the rule, but I'm saying it's legal. Right or wrong?

Can anyone provide varying releases and rubber rules in 12" 14" 16 inch??

Probably kicked terminology, so pardon the ignorance.

Thanks