Recovery time is the small period of time after casting a spell/CA that you cannot cast another. It's not cumulative with recast time, it's in a way sort of an alternative minimum recast time. The Str line final ability increases the speed of all 3 timers, casting time, recast time, and recovery time. So assuming things round out in a favorable way, you will basically have a constant all around 10% spell/CA haste. FYI, for the math impaired, it is not a 10% reduction to cast time, it's a 10% speed increase. Divide your timers by 1.1 to see what they will be with it.