It's brilliant that dd has made so much progress, sounds amazing 
How old is she?
I only ask because when my ds was at the end of Reception, our ABA consultant (I think we may have the same one, actually [winlk]) said the same about ds. We reduced the intensity of the ABA, but continued to have 20 hours a week TA support in the Statement, and it was written in that the TA has ABA training, ongoing supervision from our supervisor, and jointly agreed targets. Y1 went brilliantly, but Y2 has been doing downhill, which has been in part because the TA (and everyone) think ds is doing so brilliantly he doesn't need the support any more.
Suppose my point is that you don't really know what may happen in the future, what kind of support dd might need. And if she does need support, presumably you want it to be with the same approach (ABA-led) as you have done before, and you have to be careful that the school will continue to use the same approach. Eg my school's idea of 'support' might be removing ds from situations that he finds hard, eg playground games, rather than teaching him the skills he needs through ABA. Yet without us and ABA team, they would still think he was 'no different' from the others 
And I would never give up a statement actually, as once those hours have gone, it would be very hard to get them back. Even if the TA is used like ours is, to basically monitor from a distance, keeping in mind the targets at all times (in our case, mainly social), rather than have intensive input, it's better, imho, than having nothing.
As you say, you may need it for future schools. Even if it's with minimal hours and social targets. I would try and keep it in your position. Without it you have no idea or no guarantee really of what support the school are actually going to provide