Most of the weight should be on the rear axle.
When you get the weight with the WD bars off, you will see how much weight is transferred BACK to the front.
Your truck acts like a see-saw when you hitch up. The trailer tongue pushes down behind the rear axle, lifting up on the front axle, removing weight from the front axle and adding it to the rear axle.
Ideally you want the weight of your front axle to be the SAME unhitched, and hitched with the WD bars engaged. You're only 40lbs off, which should be plenty close enough. Given the scale error, it could be anywhere from 20lbs to 60lbs, but even at 60lbs it's still close enough.
