Have you watched Dan Ariely's TED talk on irrational decision making? Your revised pricing tiers reminded me of the discussion about tom, jerry, and "slightly ugly" jerry around the 15:00 mark. If you haven't seen it, it's interesting that you've stumbled on the effect independently.

You might find that further tweaks push more people to the agency tier by creating a "slightly ugly" agency instead of a "slightly ugly" studio -- freelancer.

http://www.ted.com/talks/dan_ariely_asks_are_we_in_control_o...