The level requirement for the tek bow should probably be adjusted now that the player level cap was decreased from 175 to 165. I am of the opinion that if a player ascends on every map on gamma (thinking solo players, not pushing for alpha ascensions, etc.) they should be able to learn the tek bow engram. As it stands with the 165 player level cap, you could ascend on every map, including gen2, and still not be able to learn the tek bow engram.
Just a thought... decreasing base player levels by 10, should probably decrease engram cost of the tek bow by 10.