No, your mileage should not be that bad. My supercharged bike saw about a 10% reduction in fuel mileage overall. But depending on your definition of 'riding it hard' you could see quite a bit less. To geek out on the math for a minute, I did a quick calculation based on a .60 BSFC (running it rather rich)... at 200hp you burn roughly .33 gallons (1.24 L) per minute.... that gives you almost 10 minutes of 200+hp operation for your tank of fuel. Depending on what gear you do said craziness, mileage will vary.... but let's assme an average of 120mph to make the math easy... that's 2 miles per minute... that is 20 miles or so (32 KM). This is a gross simplification, but it does give you some idea on how much fuel it CAN burn if you beat on it.
To summarize, your mileage is atrocious, but if you keep it wide open most of the time it's not impossible. Highly unlikely you operate it like that, though... so you may have other issues. I know from experience that if you try to map it rich in the cruise and part throttle ranges that your mileage will be hideous.... when I first did mine it went from an average of 50-ish miles per tank to 90+ once I got the idle, midrange, and cruise AFR's leaned out properly.... if I were a guessing man I'd say your problem is a combination of the two.

Keep in mind that you only need a rich-ish AFR under high load.... you should set it up to cruise as lean as possible before it starts to hesitate/buck.... I found that to be around the low 14's with my set-up. Upwards of 105kpa you can run it 12.8-13:1, then start sliding it to the appropriate richness for your fuel type as pressure increases.... and make sure your bypass (blow off) valve is functioning properly.