OK, so the question of oil control always comes up, along with the "Hey, that's a lot more refrigerant" comment. Let me put this argument in its proper context.
When you are running a supermassive reciprocating piston unit (think Harley-Davidson V-twin or Vortec V6 in size) that has a crankshaft and bearings and unloaders and "stuff", any loss of oil leads to certain violent death in short order. Many of these types of "refrigeration powerplant compressors" split off to dozens of distant evaporators in display cases and/or walk-in coolers, water chillers, office spaces, etc. There are many places for oil to pool in low spots everywhere. Refrigeration load varies drastically over a short time as people come and go, store or office opens and closes, etc. After a certain level of complexity, it makes sense to employ an oil separator and a liquid receiver to keep the extra stuff close to the powerplant.
Residential scroll compressors of your size are teensy in comparison. Unless the compressor ingests enough liquid refrigerant to wet the scroll face, the oil sticks to the scroll (by surface tension in little bitty grooves) by design. Most non-hydrocarbon refrigerants don't dissolve oil very well. I believe the Sky Air units are only designed to split off to a maximum of 4 indoor units. The piping is relatively short between units, and is much smaller in diameter than an industrial sized unit. This leads to higher velocities and less oil stagnation in the nonexistent faraway places. The outdoor unit you took the compressor out of came with 1.5 liters of oil charge, which is a lot more than you will need in your compact unit. Much of that oil stays in the compressor sump.
I found lots of data on the unit here:
https://issuu.com/vietmastec.educati...ta__split-skya
Compressor and oil data is on page 8 of the document.