Now I'm seriously embarrassed. :-(

[My own copy of SetupBuilder was v7 until I upgraded to 10 on Sunday, but I work part time for the (UK government) Health and Safety Laboratory, and I recommended that they buy it. They did and got v8. I had completely forgotten I had encountered he same problem then! And I *did* search the forum this time without success. So my .sb8 projects on the employer's computer will have the double %, but my own personal ones never needed to get that far! My problem is that I only write installers once every two or three years, and my brain cells don't last that long these days :-( ]

Anyway it has worked again. Thanks.