If by 4 of every 5 movies on DVD, then you should probably fix this by adjusting the lip synch delay for the assigned DVD input on the 990. That is, if the delay is consistently always the same delay. Which Pioneer DVD player do you have?

On the player, you can also try to change the settings for the output, ie dobly digital or PCM stream. You also want to make sure that if you have a DVD Audio/SACD DVD Pioneer, that you don't set the speaker distances and sizes here and also on the 990. I only use my 990 for speaker settings and the Pioneer settings are off/full range.