I am a sole proprietor. Why was a "blended tax rate" used to calculate my taxes?

I am a sole proprietor. I just finished my Turbotaxes and am going through the "Federal Review" section. Under "Explainwhy">"Why am I getting a refund of $????", it lists the various components of my return, such as Total Income, Deductions, Taxable Income, etc. Then it shows "Blended Tax Rate" and shows that to be 47.9% and the next line shows my Tax Liability as about half of my Taxable Income! That doesn't seem correct. I thought my tax rate would be around 22% based on my income. Is Turbotax applying the incorrect tax rate? I looked up Blended Tax Rate and that seems to be used for corporations, not sole proprietors. I worked with a Turbotax support rep for several days on these, and he agreed that it did not seem correct, but ultimately was stumped by Turbotax would apply that rate to my situation. I'm hoping someone here can shed some light and perhaps fix the program error if there is one. Thanks, Tom