Well look at it two ways:
You aim for expertise cap over avoidance, and go more FS than RS.
Or you go more avoidance and RS more than you FS.
Will it make a huge difference?
Probably not. It's a matter of opinion. You're HB is a spell, so expertise doesn't apply. BB is a spell too. So it's more of a matter of Single Target vs. Group. Single target, where you're going to have less RS than FS, Expertise is more important. When you're just spamming your HB/BB/OB when CD is up on HB, Avoidance will save you and generate more RS you can have macrod to use while you spam.