Yaris air con fuses

[Stivino]

You can’t use it on other systems because the fittings are not compatible, and designed to be idiot proof.

[Mooly]

All I way say is that armed with the appropriate information you have to make your own mind up as to what is best for you. Compressors have the correct type and grade of oil that should be used in just the same way that engines do. If you are not sure then research it more.

When you have an AC system correctly discharged (by a proper recovery machine) very little oil is removed, just any that may be coating the pipework and so gets forcefully carried out. Most oil just sits in the compressor and would almost never need to be drained/replaced in service. 

As they say, you pays your money and you takes your choice. As far as the op is concerned I don't think there is any doubt that they should get it looked at by an AC professional.