AI spell casting priorities

[Niarg]

Is there any way of ensuring that a reasonable number of gems are used for each spell.

I had an E4 tartarian with earth boots and wanted it to cast earthpower, curse of stones, earthquake, earthquake so I gave it 10 gems. By my calculations each casting should take 3 gems and cost about 100 fatigue (dominion was drain 2) however in practice the ai used up all of my gems in two turns.

I appreciate that you don't usually want to go over 200 fatigue but my tartarian had easily enough hp to cope with taking the direct hp loss. As it turned out I won the battle anyway and the one cast of earthquake hurt me far more than it hurt my opponent so maybe it wasn't too bad a thing that I didn't get the second cast off, however would there be any chance that the gems used could take into account what has been scripted and leave the necessary gems to complete the script even if it looks like it should be overridden.