I have a 2510 with Dometic 13,500 btu ac. What should the amperage be running? Mine is running 16.2 amps on medium cool. Temp here in texas today is 99 Degrees

I have an older unit (2000 year) runs 14 to 17 amps. You might gain a little efficiency by cleaning the condenser, a garden hose and condenser cleaner is all that is needed.

It would be a good idea to check the amp draw on the fan motor a high reading could be a weak capacitor or bearings starting to get loose. Without a cap tester you can check a capacitor using this formula.
Amps X 2,650 / Voltage = microfarads anything within 5% is considered good.

There should be label on the fan motor that indicates the voltage and amp rating. I put a couple of drops of oil on the fan motor shaft both ends every couple of years.

Voltage check is important, As the Volts go down the Amps go up. It appears that you are in the ball park for amp draw.
Best

This may or may not be useful:
My brother got real tired of the noise level from his Dometic A/C (he and the missus have been living fulltime in their 30' or so Avion for a few years now). His modification that reduced the noise may also have at least some impact on the efficiency of the A/C. He took metal (aluminum?) duct tape and covered up the irregular parts of the air channels so that there are now streamlined passageways for the air to get into and out of the unit. Quieted things down noticeably and probably also reduces the load on the fan motor a bit.

A kit to quiet RV ac units is available,

I have no experience with these kits however I'm aware that the noise level is somewhat annoying when trying to carry on a conversation or watching tv.

https://www.rvupgradestore.com/WackO...it-p/da100.htm

I feel that they are somewhat pricey for camper that isn't used a lot however if you camped a lot they would be worth it.