"they kill my production. "
Yes - my average is all over the place. Poping into the top 20 now and again only to decend into the pits of hades with several machines tied up for 10+ days on WUs.
It would seem that the more machines the more stable ones average would be - and it actually seemed to be for a week or so - but with the different types of WUs and loosing an internet connection plus multiple power failures and that stability vanished.
It's interesting to watch and try to stay detached.