Supercharger Oil Change
I agree with Larry -- if it ain't broke, don't fix it! As Larry stated, engine oil needs changing because it is subject to all types of contaminants from the combustion process. That is one of the reasons why engines that burn cleaner do not need to have their oil changed as often and is one of the reasons why oil change intervals on new cars can be extended.
Did you ever think about the oil in the sump of your household refrigerator compressor? The refrigeration system is a completely sealed system and the compressor is basically a piston type compressor (some new models or rotary compressors) with an oil sump. You never change this oil and the average life of a household refrigerator is 15-17 years with many exceeding this life.
The supercharger in your vehicle is also sealed and will not build up dirt as would be in an internal combustion engine. The only contamination would be possibly metal particles from internal wear. I believe the supercharger would more likely fail from other ancilliary problems not associated with old oil before an oil related problem.
If you are still insistent on changing the oil in your supercharger, maybe you also want to change the oil in the refrigeration compressor of the auto air conditioner.