That would be reasonable. I did repeated rescans and only counted subsequent rescans. For me the initial scan after upgrade took a bit more but not hours. Subsequent scans took less. E.g. 20min -> 13min for write-optimized filesystem. So that’s reasonable, although 10.10 was way faster. Library scans are expected to get faster in 13 according to some Github threads I read.

When I had the broken Home Videos library I waited 3 days for the initial scan to complete and it did not. Repeated rescans did not seem to complete although I didn’t wait 3 days for them. I’m not taking into account those scan times. Something was wrong with this library type on 10.11 and/or my media. Worked fine on 10.10.