Basic stats page (v2.2.12) is showing
MP5 531: Mouseover shows 772 O5SR.
Gaining 772-531 = 241 when going O5SR implies 2241=482 Spirit regen (factor of two because Intensity already gives me 50% spirit regen).
I believe the formula for spirit regen is 5
.003345) = 434.
So I'm seeing a discrepancy of about 10% on O5SR regen?
HT Heal: Shows 12229 (SP is 2644). I think that would be consistent with ET being multiplicative, but http://elitistjerks.com/f73/t37038-restoration_glyphs/p8/#post1240879
showed ET as adding .4 to the HT coefficient, not multiplying by 1.4.
Nourish: I don't have test numbers for these (I'll try to get them):
1) I'd assume that if ET is additive for HT, it would also be additive for Nourish. Rawr is using multiplicative.
2) I think I've heard the Glyph of Nourish bonus (and the tier bonus) are both multiplicative, so with three HoTs and both bonuses you'd have xxx1.18
1.15. Rawr has these as additive.
3) I'd assumed that the 20% bonus for having any HoT present was multiplicative. Rawr has it additive with GoN. I don't recall any seeing any tests one way or the other.