Advanced Entry.
I take this to mean that the people you are referring to as having no less than 1000 hours were Adavnced Entry types. Was that the case? How about multi time in 2000 Kg or higher? Glass? The other factor concerning experience levels is FAR part 135 or 121, or similar according to each countries standard.
Was the standard higher than stated Advanced Entry standards? I mean other than total flight hours.