Before I started to make multiple splits I used to keep good records in regards to the honey yield per hive.Making splits definitely is affecting the harvest.I have also been changing to 1/2 supers - due to age and the lack of strength to push a full super up a hill.It has also affected the yield per hive.When Varroa is reaching us, things will change.In the times when I was working double supers and harvesting on a very regular basis I would average just above 170kg per hive in a decent year with the best hive producing close to 300kg of honey in a season.WA is considered to be the best place for honey production.have a read of this:"Back in the fifties, Mr Smith kept bees in Australia?s western forests. One year, he produced an average of 762 pounds of honey from each of his 460 hives. That?s right, a 762-pound (345-kilo) average. Many of his hives made a thousand pounds of honey. His bees were all in one big apiary, in a remote forest 300 kilometres south of Perth."