at dealer? I got the regular wash concentrate (and the intensive clean stuff too). The regular concentrate says it protects down to -60F. The dilution chart only shows protection down to -10F. Does that mean full strength, or close to it, should be used in New England sub-zero conditions? Each bottle is a little less than 0.5 liter, so it would take over 12 bottles to fill the 6 liter capacity (w/headlamp washer system). What do you guys do? Just buy the gas station gallon jugs?