We're having difficulty getting Solatubes to calculate correctly for the prescriptive (option 2) method. The required ratio of top-lighting aperture sf to floor area inaccurately reflects the performance of the Solatube (we feel). We contacted the Solatube company and they agree. They have never used the prescriptive method to assist with LEED applications; they said they usually use simulation method (option 1). Solatube said they have been on projects that submitted a combination of Option 1 and 2 - Option 2 for the windows and Option 1 for the Solatubes. Is this possible?? What I really would like to know is if there any way that anyone knows of to calculate Solatubes with the prescriptive method more accurately.