The light bulb went off in my head $42 ($40 where I am) is the sign up fee to become a premium member which would entitle you to unlimited premium services for that year. Sorry just remembered that. I use the basic services because it's free and I just want to know the day before my stuff comes so I can pick it up at work before I leave at night. So I don't know why they want five more dollars again sorry I know that doesn't help.
I could be wrong but I don't think it works that way. I wish it did.
The $5.00 is a "service charge" for free members and then they remove the $5.00 for premium members. The 42.xx was for the new shipping charge for my package.
I could be wrong because they did not explain it but they said the 42.xx was for transportation costs. I think they just automatically ship it the same method as the original. That's why mine was go high.
If it worked the way you said then I would be able to do the following example.
Ship something from zip 12345 to 12345 then change address to 90210 all the way across the country for free minus the yearly $40.00