Hi Bill & all!
I can confirm your experience with the compressor speed. I've been running my fridge in Summer in the 160L setting and in Winter on 130L, as recommended by a knowledgeable fridge mechanic. My experience is it works very well and I believe puts a lot less stress on the compressor.
I have another problem somebody might have a solution to or suggestion. I have the fast and slow fan setting on my fridge, as I believe most SM 2000's have. A few months ago the slow fan speed setting started to stop the compressor and I get two red flashes for faulty fan. I've changed the fan, I've changed the switch and I still have the same result. Has anybody got any idea how to fix this? In Winter I prefer to run the fan on the slow setting. According to the Greek Frigoboat agent, the Master unit is not available anymore.