I also use Diplomacy more in a loose way, not strictly following the rules there. I usually set a DC depending on the situation. I do check the rules to base the DC on, but I do not allow Diplomacy to work in every situation, or only up to some degree. So, I basically do follow the rules, but add in a circumstance bonus/penalty, which can be huge. Hostile to helpful in combat as a full-round action is completely out of question in 99% of the situations, for example.
Bye
Thanee