As long as you do not know the factor - it can be useless - IME - most aquariums runs at NO2 levels between 0.01 - 0.03. If the factor is 50 - it correspond to misreading of nitrate between 0.5 to 1.5. If it is 100 - it correspond to a misreading of 1 to 3 ppm. Just saying that it NO2 have an interference is not enough if I should rely on the measurements in different NO2 levels - @Hanna Instruments - I would appreciate if you would publish something like this - from the manualrom Tropic Marines NO2/NO3 pro manual. NOTE - this is not valid for Hanna Checker - it is only an example how it can be doneIt worked fine for me when I use to use it. The Nitrites were almost always zero or close to zero so I stopped testing and have not bought any reagents in a long time. I suspect that you will be fine with the Nitrate tester so long as you don't shoot for 1ppm or lower.
Sincerely Lasse