A regular bike that weighs 40 pounds or a regular bike that weighs 17 pounds?
Maybe what you should look at is what other riders do on similar routes with non electric bikes. That will be the wattage that is needed to move them over that route at their combined weight of bike, equipment and their own weight.
It already sounds as if you can figure out what wattage you are putting into a particular route separate from what the bike gave you. So if you are wanting to compare your effort to another cyclist without an E-bike, then you have the number you need.............. I'd think!