I haven't tried to dedrm topaz files but that sounds about right. From what I understand, topaz is a bunch of image files, not text. After stripping the drm, you have to ocr the images and then reassemble and edit the ebook. It comes down to a
lot of work.
My suggestion is to just stay away from topaz.
The few topaz books I wanted, I found elsewhere. They were a bit pricier, but they were in epub format so I was able to acually read them on my PP