The location of your sense wire is key. If located at your starter relay it should sense the voltage currently be demanded. If the demand is light it should charge less. If your battery has a weak cell it will rmain high. I think the charge wire from alt. should go direct to batt. or starter if stock setup and not running a ford soleniod .This is a good read to explain .
http://www.madelectrical.com/electricaltech/remotevoltagesensing.shtml