What is common or acceptable Flash CPU usage?

I’m building a media player with alot of tweens in the interface , I’m wondering
what is common or exceptable in the professional flash community.

When I tween the whole Interface into another view firefox spikes to 12 - 16 cpu
on a 3.01 GHz duo-core. Is this normal? acceptable?

After the tween Firefox flunctuates between 2 - 8 cpu while idle.

I know people complain about flash cpu usage , but I’ve have never heard
what is acceptable and what is too much.

I’d hate to put so much work into something and have everyone think its amatuer because of CPU usage.