I don't see why not. However, Air conditioners create moisture. Ideally you want to set things up so the moisture doesn't pool on the deck.

What sort of air conditioner are we talking about? Window unit, or central air?

central air

It seems fine but I would recommend you take a professional help for the installation of your air conditioner. Leakage may pose a problem for the concrete deck in this situation.

raising the condenser a few feet
would be an issue for the refrig lines.

moving a condensing unit is more involved
than you may think.

can you just leave it in place & have minimum
of 6" clearance from the top? will deck be high
enough to allow access to work on the unit?

have a hvac company take a look and
give you options.

post a picture to show us the area.

best of luck

Air-con units are pretty noisy. Do you really want one so close to an area you will be relaxing on? Ask me how I know!