Extension III

This spell is the some as the fourth level extension I, except that it will extend first through third level spells to double duration and will extend the duration of fourth or fifth level spells by 50% of the indicated duration.

This spell must be cast after the spell to be extended, whether by another spell-user during the same round, or the initial spell caster or another immediately preceding the casting of the extension. If a round elapses, the extension goes for naught.