Nostalrius Begins - Quality wow vanilla realm (1.12)

Hello,
Frenzy talent has a 20/40/60/80/100 chance (increased with each point spent in the talent) to give 30% (fix) attack speed.
My pet has 1.2 attacks per second, unbuffed
When frenzy procs, my pet has 0.92 attacks per second, which is not the correct value
The correct value should be: 1.2 - 1.2*3/10 = 0.84 attacks per second
Is this happening only to me? Can any1 else confirm the issue?
Thanks

Only math that gets close to your numbers is 0.92+(30%*0.92) = 1.196 AS.
But it should work as you wrote, so something is not right.