OP, also, if your son is nearly 8, I'm assuming he's now finishing 2nd grade, and you're talking about accelerating to 4th grade reading and math next year?

It's important to understand that school principals are *freaking out* over state testing requirements. They are forced to be really conservative for fear of putting him into a testing situation in which he won't succeed. 3rd grade is a year to be terrified of the dreaded gaps if you're a school administrator. This year and next year in particular, the testing is not clear, nor are the standards for passing yet defined. This doesn't make it right, but it is what it is.

I went to go get you the table of approved instruments, and found that they have changed the rule as to how they count test scores in value added for a SSA kid:
EMIS Reporting Guidance
So assuming he's formally accelerated and scores proficient (note, of course, that what proficient is hasn't been defined), accelerating him will *help* the school's VA score. This should never drive a principal's decision, but it does help mitigate worries about how the child will affect the receiving teacher of the school's score. This is a great change, and I'm glad to see it.

Call the ODE and ask to talk to someone in the gifted office. They answer the phone and answer questions.

Here's the chart of what the state requires the districts accept: