Thanks for the update marytheres - it sounds like you are doing what you need to do for your ds and you'll be getting more good info to help understand his strengths and challenges

Re the mention of vision therapy - a lot of people pooh-pooh it, but you'll also find a lot of people (in perhaps unexpected places!) who don't. It made a *world* of difference for our dd - but when we told her school we'd be taking her out of class one day a week for two hours (over lunch, recess and quiet reading time!) her teacher was soooo so adamant that we were making a huge mistake and that there was nothing "wrong" with her vision! By coincidence, our librarian happened to overhear my discussion with her teacher and piped in that *she'd* had vision therapy for convergence issues when she'd turned 40 and it had been very effective for her. To be honest, when it was first suggested to us by our dd's neuropsych I thought it sounded like hocus-pocus but I asked around and heard from another mom who's dd had struggled with reading until she'd had VT. The *last* person I thought would recommend it was our regular eye dr, but she too said it works well for kids who's issues are caused by muscle weakness in the eyes and that the types of vision issues that are caught in a VT assessment are challenges that she would never have seen in her regular type of eye exam. So we took a leap and went forward with VT and are forever happy that we did so.
Re suggestions for what to put into your ds' 504 plan to address the hypotonia, could you let us know what's in his plan now re accommodations for classwork and accommodations? And where does his hyptonia impact him? Re handwriting, our ds with dysgraphia has accommodations allowing him to use a "word processor" for all written assignments ("wp" is our school district's code for computer/alphasmart/etc), and has an accommodation stating that he is allowed to answer with oral responses for all fluency tests (math facts drills etc). He has extended time on all classroom testing and state testing, and he takes state (standardized) testing in a "quiet" room - basically a room where all the kids with accomodations test, so it's less kids than the regular classroom and the proctor is prepared to handle accommodations. He has challenges with copying written work so he's allowed to write his answers in the test booklet on state tests and he's allowed to use a "word processor" with spell-check turned off for questions requiring more than one sentence response on state testing.
I can't remember the rest of the specifics of his accommodations, but I'm going to look them up later this week for another mom, so I'll try to remember to post them for you too. He also has accommodations that he uses that aren't specifically outlined in his IEP (we switched him to private school this year when the struggle to get his accommodations and intellectually challenging classwork in public school just weren't working out, and we haven't fought for anything to be added to the IEP since then since his current school is willing to allow him to use his technology without any fighting). Things that you might want to think about are scanning in worksheets, access to printer, how to turn in assignments that are completed on the computer (our ds used to use a thumbdrive to transfer the files to his teacher in his elementary school; in middle school he either prints the assignments or emails them to his teachers).
Pushing for understanding is probably the thing that's most important - it's certainly been our largest challenge over the years! Once a teacher really understands, they often come up with great suggestions and ideas too.
Best wishes,
polarbear
ps - one last thing that made me think of my dd who went through VT - the mention of puzzles; she never liked puzzles when she was little.