Moisture sensors on balers are there to tell you when when to turn the acid applicator up to 10.  The soft core should make a big difference on heating but you would have a better feel for that being the operator.  Get a hand held tester if  you want accurate moisture readings, probably a good idea anyway to keep your baler sensor in calibration.

Acid will keep hay just fine in the 20's from my experience.

For the guys out west...nobody in WI bales dry hay with dew on it and yes that means for a hot humid WI summer day with 75° dewpoint we only get about 5-6 hours to rake and bale our hay crops.

How much did the agratronix cost you?  Did you go through a dealer or aftermarket?