When does an AoO refill?

[KarinsDad]

I believe touching an opponent with a touch spell is considered an armed attack and does not provoke an attack of oppurtunity. You still provoke an AOO while casting within reach of them, but you can hold the charge indefinately.

Correct me if I'm wrong.

No, you are correct.

However, you missed his point.

His point was that the Monk draws off the AoOs of opponents as often as possible so that the spell casters in his group can freely cast their spells because their opponents are out of AoOs.

His use of the phrase "touch spells" is probably what made you miss it. He was refering to drawing the AoOs of an undead so that the Cleric standing next to the undead could cast Cure Moderate Wounds without having to cast defensively.