Also, Overture uses their own proprietary canonical form of multiple word terms, with the most common word, usually listed first in the active search term:
You submit "blue widgets", but the term that goes active in the account is "widget blue"
Going the other way GAW -> Overture, you run into the problem that GAW limits you on description length (2 lines of 30 chars.), whereas Overture allows a lengthy description, though they rarely display the entire description in their major distribution channels.