So far we have seen two separate 8A layouts. The 8A rooms that are divided into two sleeping areas (5020, 5022, and assume 5520 and 5522) appear to only sleep 3. There is a bed in the sleeping area, and the single flip couch bed in the other room. I confirmed this by searching for rooms on the DCL website, and these rooms consistely show when you search for 3 people, but don't show when you search for 4 people.
The other 8A layout we've seen is the one with the single double-wide room with the support pole in the middle on Deck 6. When I search for rooms on the DCL website, rooms 6514, 6016 and 5018 appear as available to book for 4 people. I'd assume that 5518 would be the same, but unsure.
We've been told that no 8A rooms sleep 5.
Just needed to bookmark this info. Right now we are booked in 9174 & 9176, but I really like the look of these, too!