Sounds like a line check. Would have been one Captain in the left seat and a first officer in the right with another captain on the jump seat doing the check on them. I expect the guy on the jump seat did the top of descent PA because the other two were busy and he wanted to help out as maybe had nothing to do at the time. Also if it was a new FO there may be a requirement to have someone on the jump seat as a safety pilot but this is almost always another first officer as it is cheaper so my best guess is a line check. Maybe name mix up in first PA if you remember the name as the first officer but he later introduced himself as captain.