This is the worst washing machine I have ever owned.  I do not recommend the washer with the impeller.  Nothing stays balanced.  It constantly stops and restarts.  Nowhere near energy efficient.  Most loads take twice as long because they become unbalanced so easily.  The load size and wash cycle have no bearing on the load staying balanced.  Only suggestion is to have an incredibly expensive repairman come out and take a look.  Maybe the machine with the agitator is better, but the impeller is awful.