If the user is holding an item, then Technician will come into effect (so, 55 base power becomes 82.5 base power). If the user is not holding an item, then Acrobatics will be 110 base power, and Technician will not come into effect.
So Technician does boost the power of Acrobatics, but not if it already has its power doubled.
Source: Experience, and I'm sure I read it somewhere...