Quote Originally Posted by Leidiriv View Post
Okay, say we're at 200 mana (or, since we're not barbarians and want to guarantee the Stone/Fire proc off Holy/Flare, 199). We can't possibly generate any more mana. Does the melee combo still have the extra "cost" of the 28-35 mana you could have generated in that time?
That scenario isn't worth considering until we've already assigned value to a point of mana. What we are interested in are question like
  • Should I spend my mana on E.Reprise or should I spend it on E.Riposte...Scorch?
  • Should I spend my mana on E.Reprise or should I waste mana by overcapping?
  • Should I spend my mana on E.Moulinet during this trash pull or should I save it for E.Riposte...Scorch?

If we're going to answer these questions, then we need to take into account not only the mana that we're spending but also the mana we're not generating because we've given up a certain period of spellcasting in order to perform the spender. Spending X mana doesn't delay the next spender by X mana. Because all the spenders are on the GCD, they meaningfully delay the next spender by the mana that would have been generated if you'd used generator actions instead. Therefore, we have to take into account the foregone mana as an additional cost of using the spender. Only then can we measure one spender against another. Then, once we know what each spender is worth, we can set our expected potency-per-mana based on the spender with the highest return. Then we can assign value to the overcap mana in your scenario and arrive at the conclusion that it's obviously a damage loss to continue to cast spells if you're at 199 and you have the opportunity to perform a complete combo.