I have the exact model/year Thor Residency as you have...
The only way I can see that you can count that it 'sleeps 6' is the following:
2 in the rear bedroom
2 on the couch that folds out into a bed
1 in each of the captains seats at the front that turn completely around to face the back and somewhat recline into a sleepable position.
I don't see how it is possible for the dinette area to conform into any type of sleep area.
Hope this helps!