Hi, thanks for your response!
Some of the things he missed were simple, like mistaking an addition problem for a subtraction problem, or vice versa. But even then he would do some of the addition and subtraction correctly. He missed both algorithm and mental math problems, and even word problems like, 2 candy bars, one $.55 and one $.35, you give 4 quarters so what is your change? He answered $.20. Some of the answers are so odd I almost think he might have a kind of number dyslexia.
Thankfully I'm going through a public charter and the extra expense for the guides, or even for more one level per year, is doable. I also have the help of an instructor who is familiar with Singapore Math that I'm going to share his placement tests with, so hopefully we will figure this out. But it looks like I'm going to have to start over entirely in Math with him.