Not that specifically. I switched from standard to PWYW after a year of sales and I felt I had made enough and wanted it to be open. I still get decent sales, but the majority of income was always from print books which are not PWYW
I personally appreciate this approach, I tend to do a first pass read on ebooks and if I find it of high value and the subject is not temporal (e.g learn Flash development). I always purchase the physical book for my library. I don't mind paying twice, if I have some confidence that the material will be of value, but it does cause me to pass on some texts that I may have found worth buying the physical book had I not passed on the ebook.
