I'm also having this problem. You have to move onto making level 15 proficiency recipes at 15 so there is no question of making something closer to your proficiency level. I've been making adventurer garb and have managed to get to 16%/15, used so many bird wings. Only half of the garbs give me 1%, the rest give me nothing.
From what I seen so far. Tech is suppose to increase success rate in production and increase difficulty level of whatever equipment you're trying to make, not Proficiency level. When my pro was level 11(and of course when my character's level was 40), I started adding Tech (Which is now 29 I think), nothing happened, just my difficulty increased, which is good to start creating better equipment.
The more difficulty you have have, the better equipment you can make, and the higher the percentage it will be on leveling your proficiency. So in specific, Tech does not increase the proficiency level itself, only difficulty and success rate. People can call it a faster way to level your pro.