Just running a quick experiment ...

Ragstone Grinding Wheel, level 11 CRP craft.
1st time craft : 3420 bonus exp
Base exp : at level 11 : 1140 exp.
Full Quality is 300% bonus, plus 50% rested = 5130 exp.
Ash Lumber : 917 base exp. Full Quality + Rested = 4126 exp.
Grand CRP total : 9256.
Leve for hand in in : 14940 exp. 29,8880 if HQ.

So, by not making the stuff, using this one LEve as an example, you’re giving up 25% of the exp.

Do the math on other Leves. 25% was on the low side compared to years ago, but it may be the norm now.