Owen...Describing has nothing to do with being new. Do your best to be as descriptive as possible. If you don't understand what we are saying when we mention you gave us little to use. Take a look at your first post. When I read it (and I have ESP usually) what I see is you saying. "I hear a noise, my SC oil was changed, could it be the SC?".
My thoughts on that are, sure it can be. However knowing more, like your second post. "Sounds like a belt rubbing, there is a lot of belt wear". That gives us much more info to go on. You noted the wear and sound of a belt wearing. My questions to further the info are:
How is the belt wearing?
Only on one edge?
The wriiting has worn off?
The ribs are cracked?
Have you heard of the screwdriver etc trick to listen to things, or do you have a mechanics stethescope (cheap tool, super useful). Those would allow you to listen to various things and have a good idea of what may be bad.