PC version of my avatar avtr_e2f46107-6f79-4703-b26d-65655a1d1fcd has two physics colliders: a trigger for a seat on the shoulder and another one for collider flight.
When uploading the avatar, the SDK builder window says the avatar has only 1 physics collider. However, in the game the uploaded avatar will have 2 physics colliders in the avatar details making my previously good ranked avatar now a medium.
It looks like the SDK ignores colliders in regards to performance ranking if the same object has a VRC station script on it but server processed avatar ranking doesn't do that.