This tends to have the effect of ruining it for everyone, as buyers develop the expectation that they shouldn't pay extra for the augment slot when in truth they should, as it represents an improvement they can't duplicate without non trivial expense, not to mention time and trouble of locating a crafting table and acquiring an augment kit.
Because its not worth it
I craft tons of implants of any level (21,25,29,33,37,41 and 45) and anything below lvl50 is a waste of an augment slot cause noone will augment or use an augment for an implant while they are leveling
Even BH implants with augment slot the price difference is not even worth it cause you sell maybe one or two a week if you are lucky
Even Hazmat implants they are so expensive that again 60 k more or less is not gonna make you turn around when the implant goes for 1.7 m and you might see just one or two at the market if you are lucky
So basically the whole augment slot for implants at any level doesnt add anything, much better would be to have another implant made, that way it would be actually worth something to have a crit