"Since we're getting deeper into the subject than simply adding refrigerant,"

Your system was opened up to replace hoses ... is that correct ?
If yes.... and you know I am not psychic...that there is a reason I think this... then you were past " simply adding refrigerant" before you starting typing the first post...

Since you are at that stage you need to consider flushing your system... you really need to read all you can on the Aircondition.com site first to understand the basics of AC theory...... then come over here to ask questions specific to your car and MercedesBenz....

Another thing is that there are MOUNTAINS of posts in threads already on this site.... a bunch of the posts in them are me trying to convince people to follow the rules of physics and proven techniques for long lasting good working AC systems...

Putting the right amount of oil into a system is a big problem for everyone.. lots has been written by me and Larry Bible about that...

The safe way is to flush the system and measure clean new oil into it when you charge it up with refrigerant.

Have you read any other threads on this site about AC recharging or fixing ?
Until you understand the basic theory you will not understand why you can't jump to the end of the process and your AC fix be successful...