Master Enslave MR roll

[Pocus]

I start to seriously wonder if something is not working unexpectedly for this spell. It is supposed to be "MR negate easily"... Now I have to wonder how it can be that I loose so often leaders in the MR 20+ range against the casting.

Last time, it was:

Oracle astral 12 + 3 MR breach from items against a vampire lord MR 23.
If I calculate right, its then - 1 MR (-3 from items, -2 from being 4 levels above, +4 from MR easy) against MR 23, so it lead to MR 22. And I lost this one too. This is not the first time also...

So:

1 - several very unlucky rolls (and I mean rather unlucky, you have 3.03% chance to fail the roll above).
2 - its written MR negate easily, but the code use MR negate.
3 - the gain from high caster (level 12 versus level 8 astral) is in fact used like this: 12/2 = 6 bonus, and not (12-8) /2 = 2 bonus.

4. something else.

But it dont smells right. After "exploring" the fact that winged helmet has lost its additional power (one army trashed in PBEM), now I'm discovering some other nastiness in dom end game (another army trashed...).