I'd use caution with the trust placed in any test kit available at the hobby level. More often that not, these tests would provide different readings within every testing. To assume the measurement down to decimal point accuracy in most cases isn't necessary and to chase such numbers is a waste of time in my experience. After every test from any kit, I use some skepticism in the precision it offers and assume it to be within a window of the result provided. As long as my results are within a consistent range, my tank stays happy.
I use Hannah testers and API, and more often than not I find myself testing with API as it gives me a quick idea of where my levels are. My tank is full of 50+ acros and I've yet to lose a coral because my Alk wavered a few decimal points. I would worry more about constantly changing dosing formulas and tinkering with the tank based on testing results.