It didn't look good to break in on McCain. It's customary to let the concessions come first.
Could it be the camps decided on a time and Romney took his time regardless of when McCain's speech ended? Huckabee went on late, throwing off the whole rotation. Still, it would have been better to keep an eye on the TV and gone after McCain.
Or, is the McCain camp fanning flames?
Who's ready for a Romney/McCain ticket! Git yer fightin' and fisticuffs all on one, convenient ticket!