Is it normal to have the volume change dramatically on some chanels?

Unfortunately yes. This is one of the reasons I bought a Denon AVR with Audyssey Dynamic Volume Control. It eliminated the volume change problem between channel changes and commercials.

But the new SC firmware eliminated your Denon AVR ? (for video switch). ;-)

But the new SC firmware eliminated your Denon AVR ? (for video switch). ;-)
No it did not, it switches just fine on my AVR component inputs...