I guess I'd ask if you think the tantrums are because you won't do what she's asking/requiring of you and she's mad at you, or because she's afraid or troubled that something "bad" will happen if you don't do it, or simply because it MUST be done--utterly external to her as far as she's concerned--and she honestly can't conceive of it not being done.
The former is no big deal, I think. The latter two might be more of a problem.
BTW, that she wants *you* to do the actions, and they're not something that *she* does also makes me think it's unrelated to OCD.
One last thought: have you asked her why she wants this stuff done? Sometimes the answer can be telling about what's on her mind and how to approach it.
