This is why you should never trust a guitar store that does while-you-wait set-ups. Any set-up certainly needs at least one overnight waiting period followed by another check. Very small truss rod tweaks don't normally take that long to settle down, but anything more than 1/4 turn and you're better off waiting a good while before checking again.

To get your action as low as possible might require some light fret stoning and re-profiling. But one step at a time.