I'll ask again - are you talking level or skill? You keep saying level but I think you mean skill. Skills are shown in your Persona Window in the Tradeskill tab. Yours will be something like xxx/100.
You missed what I said above.: You
must use white-con arts (in this case your level 20's) to get regular and reliable skillups. Your skill cap goes up 5 points every level; if you use those white con arts for a couple of combines you'll get your 5 skillups and then you can go back to using whichever ones you prefer.
So, to get your skills caught to your cap, use your newest arts.
Skillups are tied directly to using your arts and you gotta use white con ones to get them. This matters less as you level up and the arts stay white longer; and probably won't matter at all when Kunark launches and we get the promised TS Art revamp.
BTW, you get more XP for white-con recipes, you're robbing yourself of XP by only doing blue recipes. The trick is to use
both progress and durability Arts, not just the Arts from one Tier (there's lots of right ways to apply your Arts, but only using one Tier's 's arts is one of the wrong ways).
Try one of these guides:
Understanding the Arts - How to Successfully Apply the Tradeskill Arts
Power to the Pristine - It's all about the buttons
Pristine - how to get it (almost) every time Not a Moment to Lose! A Guide for Power-Mad Speed-Crafters