Wasn't there a Q&A thread by a guy named Joker, who was spilling some imm secrets a few years ago?

I remember him saying that Calming wasn't just straight -20 svspell.
In addition to this, it actually let you have a *second* saving throw on anything spell related.
So basically, if you failed the first check, you got a free second one.

This sucked if you had a low svspell, but with a high one, no spells/communes would land on you (or you'd save significantly, for lesser damage).