slammie- I completely know where you're coming from. High IQ doesn't correlate with making good decisions, having emotional self-control, or attention to detail (at least not in my house).
There are moments when I absolutely question whether DS7 belongs in DYS- sometimes there are things he "knows" how to do, but freezes on due to anxiety and emotion. There are all kinds of inconsistencies- and we occasionally get calls from teachers too (esp. for goofy, disruptive behavior).
I want you to know that you are not alone. We have resolved math for the moment with enrichment at home. It works fairly well in the earlier grades-- but admittedly will be an issue when DS gets to be older (if he doesn't slow down). We're just not crossing that bridge until we come to it.
Maybe the grade level math will be okay-- it may be a bit boring, but it may teach your DD to think through "how" she solved the problems- without the pressure of more difficult math. DS7 does a lot in his head too- it's impressive most of the time until he makes a careless error and becomes upset. We're currently working on some things that DS needs to understand- and it's hard to understand without seeing all of the steps.
