Is there any real difference between anusol-hc 2.5% and a generic hydrocortisone 2.5% cream?

No. The difference is in name only although there may be additives that are different.
Anusol-HC 2.5%. Anusol-hc 2.5% is the brand name and Hydrocortisone 2.5% is the genetic. Anusol comes as a suppository while the generic is a cream. The suppository may be more effective for your condition.