Voyager: What is the difference btwn. D1 and D2?

I have a 9th floor D1 balcony cabin (midship) on hold for a 3/07 Voyager cruise.

What is the difference between a D1 and D2? I know D3s are on lower floors. But D1 and D2 cabins seem to both exist on decks 8 and 9. Some D1s are on deck 10, and I understand the corner aft D1s there are larger and that all aft D1s have bigger balconies. But aside from those afts, what is the difference between. D1s and D2s?

Are D1s any bigger?

Thank you in advance.

I would have to say location.

Some D1 cabins have a 3rd or 3rd/4th berth. D2 cabins only hold 2.

D1's are on the highest deck having D cabins (usually Deck 10) or hold more than two people.

On the Mariner, we had a d1 and a d2, next door to each other, the D1 held 3 while the D2 only held 2, aparts from the pullman bed, there was no difference