Low Order calculation problem?

I'm trying to use the low order extension. I have it set to
Order Total: 20
Fee: 5

I thought that meant everything $20.00 and below would be charged $5.00. Instead, what I'm getting is this:
The Sub-Order Total is $25.74
Low Order Fee: $8.17

Not only is it ignoring the $20.00 limit, it is calculating something beyond the $5.00.

Am I wrong in my understanding of this mod?

Do you have tax enabled for the fee? Do you have your currency set to 1.0000?

It was the value of the currency . . . not set at 1.00 but at the default. Thanks!