I have three Ice chargers. I use them for two Orion 4800s and one Orion 3200 After a full season no battery is out of balance by more than .01 volt.
Interesting that you bought some Lipos. You only need one per car. I have never pulled enough current out of one to not be able to be charged for the next heat race. I have run in carpet oval as well as dirt off road. It is also possible that you are running several vehicles.