I've used the traditional "replace all the weight from the front" and the Ford recommendation of 50% and believe me the new trucks handle best with the 50% replacement. Not sure why you're doubting the scales though since adding weight behind the axles SHOULD lighten your tongue weight. I suspect your confusion is coming from using empty weights (from the brochure) and trying to compare them with real world weights which are always a lot heavier. As long as you're towing OK I don't see anything to be concerned with in your weights.
Good luck / Skip