Supermagneto Pro Setup Powercurve

So I have a Supermagneto Pro and setup is as recommended to the letter.  I am also 6ft and 270 pounds but an avid rider all year.   With my setup with actual statistics entered I found that I could not get my speed or power up to a realistic number with out an all out sprint.  If I am riding a flat at 18-20mph on wahoo bolt it shows me at around 10-12 mph and if I hit any incline I drop to about 2mph even though my HR is 145-155 bpm and my power does not really go over 100.  I found if I lie about my height and weight I can get it to a realistic level but there must be a better answer.  Knowing my personal power level, hear rates and speeds the zwift output is not even close or even fun when I can not keep up with an old lady with a mobility scooter.  Any help is appreciated.