When calculating if the test is routine, difficult, or challenging, you’d always look at the number of dice (from skill, forks, traits, help, advantage) actually rolled (except those dice gained from Artha) against the obstacle you are trying to meet.
For determining how many routine, difficult or challenging tests you need to advance, you’d look at the current rating of the skill, which in this case is 2.
For advancement purposes, you have a 2D skill. You need 2 routine tests and 1 difficult or 1 challenging test to advance. However, as with any other time you test, to determine the difficulty of any given test, you count the total number of dice you’re rolling (including the 2D from your trait, but not including any Artha spent) against the obstacle. If you roll 4D against Ob 2, that’s a Routine test. If you roll 4D against Ob 4, that’s a Difficult test.
I agree with you. I had thought at first it would be clunky, but I have a few of the charts in a little booklet printed off for reference, and it is quick, simple and AWESOME.