My HVAC contractor installed by Carrier condensers on two new pads. The are not concrete. The contractor used stone dust underneath the pad to level the ground. I was not present during the installation. They seem level, but I have put a level on them.

The contractor is not going to be happy about disconnecting the lineset, and I am not sure if you want to take the risk of compromising the connection.

I don't understand why putting a shim underneath the concrete pad will cause a problem. If you do place a wood shim, it needs to be pressure treated wood for ground contact. A slope of 1/4 inch per foot is the general rule of drainage on a patio. It sounds like you are within that slope, so I don't think you need to loose sleep over this.

You can shim the pad. A 3/4 inch rise will pose no issues with the lines. Use a thick piece of rubber to help minimize vibration noise. You can buy rubber feet of various sizes that serve the purpose very well. I would suggest to shim the unit and not the pad if looks wise, it will be unnoticed. That will minimize noise.

Yes, a slight drop does help drain water since it has a tendency to run down hill. The units are made to take water drainage into consideration on a level pad.

Your particular issue is more cosmetic than anything and like you, I would prefer them both to look the same. You will get less long term wear and tear on a level unit but the manufacturer knows this isn't always going to be the case and has built in allowances. Think about it, if a tilt was so critical to drain water, the tech should have tilted the other one too. You can ask the installer if he would level the unit but just know, it is installed according to specs. and he might push back. I personally would have made them both look the same one way or the other because I know people look at that sort of thing, I surly do.

The unit is mounted on these feet ("pump ups"?) to allow clearance underneath to blow leaves and reduce corrosion on the bottom of the units. He put some shims between the pump up and the unit that you can's see. That allows the pad to stay as-is, and the unit to be level. We measured the one next to it, that appeared level, but it was off too (in the opposite direction). So he put shims on the front of one and back of the other. Now perfectly level.

Thanks for the feedback!