You're probably right because the max GVW on a single axle is 20,000 lbs but my source is the USDOT sticker on the license plates of several Fedex and UPS truck

You're probably right because the max GVW on a single axle is 20,000 lbs but my source is the USDOT sticker on the license plates of several Fedex and UPS trucks that deliver to my suburban address and my parents' exurban address.