Help with Paladin fightclass spell

[kallekalas 1]

I have a paladin who uses most of his spells. I've made it so when Paladin gets to 30% mana he switches to Seal of Wisdom, and when he gets above 30% he switches to a regular damage seal.

My problem is that now the paladin is just bouncing between 25-35% mana and keep switching the seals. Is there a way to make the seal of wisdom go all the way up to full mana before switching?

Edit. I play on a wotlk server.

[Marsbar 228]

Change the damage seals mana condition to be 95%, make it higher priority than the mana one and have the mana seals condition to still be below 30%.
It will use dmg seal till 30% mana, then switch, then when you reach 95%, it will switch back to dmg etc.