Nev the 985 wazza good engine, yes some would use a bit of oil. The main reason for that was maintenance and running over time. It was considered normal practice to run over 2000 hours on AG aircraft when the TBO was initially 1200 then 1400. On Ag use it was mainly topdressing or super, a load every 6 minutes or so, that's full power (36" and 2300 revs) back to max continuous a touch of cruise then landing, every 6 minutes for 2000 hours. I have seen 985's run to 3000 hours, it wasn't much good for overhaul just throw it away. At the time you could get an overhauled 985 for under 20K so some treated them as a throwaway engine which was a shame. I used to pull mine at 1400, most were burning less than a litre an hour. The worst I have flown was working for a particularly dodgy operator I had to top up the oil during flight, the oil was running very low before the the 2 hour fueling. Used to have a watering can of oil on the passenger floor. Oil tank used to hold 20 litres. The only aircraft with a worse oil burn was a Dromader, all of those used to burn/leak/throw lots of oil. The oil tank on a Beaver was inside the cabin for arctic operations you could refill the oil from the cabin after using the oil dilation function to get a quicker spinning engine in the cold temps.