Bah. The problem with most of these reading assessments the schools use is that their function is to highlight problems. To pin-point children who are behind in reading. They are NOT designed to accurately reflect your child's skill level - especially if they are reading several grade levels above their current grade.
Good luck to you in convincing your hubby. I think mine would have been thrilled if things had worked out so that I was a SAHM and home-schooled our kids (he was raised by a SAHM and was homeschooled), but things didn't work out that way.