so just wondering when you spend the focus to change 1 focus result to a crit does it still flip your other focus results to hits? So say I roll 4 dice and I get 2 focus and 2 blank. I use calculation to change 1 focus to a crit and the other focus stays unmodified?

No to the first sentence. Yes to the second sentence. Calculation gives you the option to spend a focus token to get that one crit instead of turning all your eyeballs into regular hit results.

Ok cool just wanted to make sure, thanks.

If it was the other way around, it would be a better Marksmanship for 1/3 of the points. That should've answered your question.