Am I overthinking my blending math?

How do you work out quick proprtions? My method is to start with a base and slowly add one material in 0.02g increments, putting the result at every single step on a test strip that i dip into the container.

I’ve started factoring the 'test strip loss' (my scale says mostly 0.02g) into my spreadsheet. Since every dip takes a tiny bit of the mixture with it, the concentration of my starting material actually drops slightly more than if I just kept adding to a closed container.

Am I making my workflow harder than it should be?