They never really went into detail, their whole argument was that if you wanted to use Diplomacy, you did so by default at a -10 penalty (for doing it 'rushed'), or it would guaranteed fail, for the above reason. :(
Changing others’ attitudes with Diplomacy generally takes at least 1 full minute (10 consecutive full-round actions). In some situations, this time requirement may greatly increase. A rushed Diplomacy check can be made as a full-round action, but you take a -10 penalty on the check.