There is a phenomenon of 'minimum activity fatigue'. I've flown five shorthaul night freight sectors with less fatigue than flying two, with a five hour break in a crew room between. Same duty period. Even with long haul, a turboprop with a relatively high cruise workload is to a cetain extent less fatiguing than a lower workload jet aircraft over the same FTP. The landing at the end of a longhaul flight can often seem like starting a new day's work, or at best a split duty