Did they change refridgerant type in newer A/C's ?

I think the campers just keep getting bigger We got our 08 new and the salesman said the 15,000 btu AC would be enough to keep it cool. Well it works 90% of the time but that 10% you need the extra cooling you REALLY NEED IT! I wish we would have put the 13,000BTU one in the bedroom:{ live and learn or add one or suffer through the heat. The saving grace is we are at the lake in the water on those hot days instead of sitting in the camper.