I hit 0/99 leves 3 times when I was leveling miner to 50 (waited for them to regenerate full between each time), then waited till they regenerated back to 99 and hit 0 again when leveling botanist. It's quite possible to do it as I have done it 4 times now, but it required several hours of leves each day.

Its very easy for players who play all the time every day, but I'd imagine itd be VERY difficult to do as a casual player.