Ball python weight gain, is this normal?

[hungba]

I have several ball pythons. There is one female lesser that when I got her last year in mid November, she was 99 grams. She refused to eat under my care for 3 weeks, and as I posted in another thread, I gave her to a more experienced friend to get her eating again, I think that was about mid december that I gave it to him.

He got it to feed again right away with no problems, first couple meals live, then since she ate again, got her on F/T with no problems. He was feeding her MICE only, NOT rats, every 4 to 5 days, he told me. He said that as she grew bigger, he increased the mouse size. He didn't weigh the rodents but he said they got up to adult mice "about 40 grams". The last two meals before he gave her back to me, he got her to eat f/t RATS, as I requested he convert them to that for me.

Meanwhile I am feeding my other balls RATS of appropriate size every 5 days.

He gave the snake back to me about 2 and a half weeks ago (not sure exactly), and she has since taken 3 meals with me of f/t RATS of 45 grams every 5 - 6 days. She skipped today's meal.

The thing that worries me is, she seems to not have grown as much as my other balls, although I must say that those other balls are feisty eaters and fast growers. They are not exactly the same age but they seem "impression wise" to have grown more, and look "fatter". I weighed her today, and she was 308 grams, this is EMPTY weight, fed last 5 days ago. I didn't weight my other ones tonight because they just ate.

Should I be worried yet about that? She went from 99 grams to 308 grams from mid december 2011 to today (about 4 months), is that very little or ok? If its in the normal range of weight gain, then perhaps its just different environment at my friends house vs. my house different feeding etc.? Or he was feeding mice instead of rats?