1998 290 Sundancer with twin 5.0 EFI and alpha 1 gen 2 drives. Never had this before. So took the boat out this week on a flat bay day and throttled up to go on plane. after it lays down i normally pull back to like 3800 rpms and both motors sync up nice at 25 knots. This last trip I planed off and when i pulled back i had to have the port at 4100 rpm and the starboard at 3800 rpm to have the sync in center. motors sounded strong and ran great and did not skip a beat. Should i go by RPM or by SYNC. Thoughts? have not taken out since that trip so not sure if it was just a fluke of something i need to address.