it is.
Yes, kinda. Thats where Im having doubts on your test results. Even in R Farley's article on corrections he does frequently mention minor test error, esp when its noted the two are out of balance.
He goes on to say it testing error is unlikely imbalance is likely due to human error and unbalanced dosing. So in your case Id have to guess test error. I think at 7 alk youd be in the 400 cal range or a bit less.
Heres 2 articles.
A dry read but look at the first yellow chart under cal alk probs. you should fall in the red range.
http://www.advancedaquarist.com/2002/11/chemistry
And although this is talking about 2 part dosing the usage examples are very helpful and easy to read.