RevFire readings - stationary vs full pitch

I am pretty much new to softball, so please excuse my ignorance, but my just recently turned 11 daughter is a pitcher and wants badly to be good so I want to do everything I can to help her achieve her dream. That's going to mean educating myself, hopefully as quickly as possible. Her pitching coach turned her fastball into a dropball and I am seeing that RPS is very important for that and long-term success, so I bought a Rev Fire so I could see where my daughter was at and how far she had to go to get where she will eventually need to be. It measures her between 16 and slightly over 20 RPS. That is more than I expected for a 10 year old (sorry, 11 now). I would assume that's good? She doesn't always get the proper rotation (12-6?) so sometimes it's more of a curve, sometimes even kind of a screw, and sometimes it doesn't move much at all (bullet spin?). When the rotation IS correct, she does get a pretty good drop. I know she has to work on getting the proper rotation, but if she can get that down, can I take any meaning from those RPS numbers? She throws between 38 and 44 mph. Her coach says her mechanics are really good. She's been pitching for a year and a half. Was hoping some of you vets could give me some help. I have a lot more questions.

Mark- the best thing you can do to take full advantage of the info and resources on this board is to post some video of her pitching and to compare her to the pitchers mechanics in the model pitchers thread and to read the I/R in the classroom sticky thread and see if what is taught there seems to match her mechanics. If her mechanics are sound then moving on to spin rates may make sense, but more often than not, new posters here have kids that need mechanical tweaks to their basic motion before they worry about spin rate.

I've been soaking up the stickies, etc. here and her mechanics seem to match what is being taught here. She is far from perfect, of course, but her pitching coach teaches the same things (no "hello, elbow", elbow whip, etc.) and she is generally successful. She needs more consistency... some times her hip gets in the way, some times her arm is off-center, she definitely needs to use her legs more, etc. I will post video when I get a chance... I know that's the only way to get real feed-back. Thanks for your response.

2 weeks ago my 9yo's pitching coach pulled out the RevFire, my dd has been pitching the 11" ball and 35'. The Revfire ball was a 12" and shepitched at 40". She had readings of 42mph and 12 to 13 rps. Not to bad for throwing the bigger ball and the longer distance.