So there are Prof Lvl/Conc Usage Breakpoints Within Quality Levels?

I'm trying to figure this out. Messing about with gems on an (underleveled & undergeared) JC.

So flawless cuts use 1 gem and 5 gemdust.

• If I start with all t1 mats then swap to t2 gemdust 1 at a time each one saves 3-2-3-2-2 concentration (on this character it maxed out at 178 skill).

• If I start with a t2 gem and t1 dust, swapping dust each time saves 3-2-16-50-54 concentration (small improvement between skill 183-199 and big improvements after that).

• If I have all t1 mats and add 30 levels from filling out a specialization node I save 5 concentration (going from 100 skill to 130).

• If I have all t2 mats and add 30 levels from filling out the same specialization node I now save 102 concentration (going from 230 skill to 260).

• If I start swapping t1 gemdust for t2 in that last example I lose 54-51-54-51-12 concentration (the last dropping from 198 skill to 182).

In all examples t1->t2 gem was worth 65 profession levels and each t1->t2 gemdust was worth 15/16.

So I guess there are hidden break-points between an r1 and r2 gem craft where increasing profession levels begins to dramatically cut down on concentration costs? And for gems this is around skill 200?

If anyone knows of a blog post or other write-up on this I'd appreciate knowing more (especially for equipment crafts with more than one quality level).