Which A/C oil? 2000 W900

I would check the oil in the compressor like @BoxCarKidd suggested. I usually put a little in each evaporator and the condenser.

I don't think those oil charge cans are a bad thing either. I just don't think that it will get to the dump sump of the compressor by using them. With not taking the compressor off I'm sure your fine just doesn't hurt to check. I would probably vacuum it a little longer than normal and make sure its above 70 degrees ambient temp. Just to insure you boil all the moisture out of it

 

In my opinion that is enough oil that your are OK. It is better to be a little low on oil in a system with a big compressor than mix unknown oils. I thank mixing mineral oil and others is what really mucks stuff up. I am not sure about all of the others. I am asking.
If oil is added into the lines I believe it will be stabilized into the system and will work its way to the proper level in the compressor.
The rotary, roundy boys, can even be flushed out while mounted on the truck. Then you are starting from scratch. The oil is all the same, oil and freon amounts are correct. AC should be good.
Most expansion valves are replaced for no reason. Just back flush through them. It is a bit of a slow process.
Thanks for the @BoxCarKidd 's! I really got on this sight looking for information but find myself trying to help other people more. That is OK because if I help 100 people and someone will help me one time in return I am ahead! The @BoxCarKidd does not go to my Email anymore and I am not sure how to fix that. Running equipment and turning wrenches is more natural for me. Can anyone tell me how to reverse what I messed up?

 

In a compressor like you have just put oil in it like adding engine oil and use the dipstick. You could also poor or suck some into the lines.
With a roundy boy I like to have as much oil in them as possible. Then spread some oil around the system depending on what lines are open. Pull a vacuum on the system and have a premeasured oil container. Close the red manifold valve, unscrew the hose below it and stick it into the oil container. When the container is empty hold the hose up being sure all the oil is in the system. Wipe it off and screw it back onto the gauge set. Allow the system to finish vacuum through blue side.
When finished I prefer to have a power wire I can connect to the clutch while I watch the gauges. Oil and or liquid freon deadheaded to an expansion valve or orifice can cause high pressure. I can watch the gauges and control the clutch preventing a compressor crash.

 

If you get the single shot dye syringes you can refill them and add oil through the low side charge port. Easy to measure out the amount your adding too.