Your normal male sounds fine if he's in good body condition. I wouldn't worry about him at all.
There is no set "normal" size for BPs, females or males. They grow constantly throughout their entire lives.
Super large males are uncommon, but not unheard of.
Males can be sexually mature at 620g, yes. But 620g for a male sounds more of a juvi-sub adult in my opinion.
My adult breeding males average in the 1000-1500+g range and still growing.
Some people here have larger males that that.
Edit: decensored beat me to it!