I think it's just a rolling one week timer. i.e. no set reset, just one week after you started getting Sp basically.
^ is correct, but a few more details
Surplus is based on the class.
Lets say I play Conjurer, Lancer, Weaver, and are sub 50.
Day 1: I go out and kill stuff with conjurer. I hit surplus.
Day 2: I go out and kill stuff with Lancer. I do not hit surplus
Day 3: I go out and kill stuff with Lancer. I hit surplus with Lancer.
Day 4: I weave and do not hit surplus for Weaver.
Day 5: I go out and kill stuff with Conjurer. My surplus resets due to lancing and weaving, but I quickly go back into it.
Day 6: I weave and hit Physical Level Surplus.
Day 7: I take a break.
Now. On day 8, a multitude of things can happen.
1) I kill stuff with conjurer. Upon getting my first SP for conjurer, my surplus will reset for conjurer. In addition, my physical level surplus resets the first EXP I get, no matter which class.
2) I kill stuff with lancer. In this case, my conjurer is STILL IN SURPLUS. Since my lancer resets tomorrow, my lancer is in surplus as well. However, the first physical EXP I get, my Physical rank surplus resets.
3) I weave. Same thing as #2.
Now on day 9, it's pretty much the same thing. However: I got my first SP with lancer exactly 7 days ago. This means that my lancer surplus is able to be reset, even though I didn't hit surplus until Day 3. It goes by when you FIRST got SP/EXP.
So you keep surplus until you hit one monster, and then it all goes away on reset day. Each class is on a separate timer, including physical rank. Also, there is no "Shared timer" between everybody. My Conjury/Physical surplus resets every wednesday, and my lancing surplus resets every thursday. (And if I keep doing archery this week, my archery will reset on sunday) Edited, Nov 8th 2010 12:19pm by Meowshi