This seems broken. I know it's mroe or less the same in all games but it seems that a character with an augur implant doesn't lose out from switching his implant on. He gets all the benefits, never has to switch it off, nor has to lose anything/compensate while it's active. All those bonuses (depending on craftsmanship) are active.
Conversely using an Augur as a device, not an implant, doesn't seem to require any action to activate. Unlike the cybernetic equivalent, there is no mention of requiring a half action to activate. Again no mention of how long it can remain active or the process of deactivation.
Surely then the first thing a Techpriest with an Augur implant will do is switch on. Then it remains active and he enjoys a hefty benefit for the rest of his life!