Just trying to get things clear in my mind. Lets say you spam the key each second:

1 PoM Casts with 10 sec cooldown
2 Renew casts with 15 duration
3 PoM Cast fails
4 PoM Cast fails
5 Renew casts and 15 duration starts again (waste of mana?)
6 PoM Fails
7 PoM Fails
8 Renew casts and 15 duration starts yet again (waste of more mana?)


What am I missing here? You try and press the key 5 seconds apart?