Very nice. That's exactly the sort of thing I was looking for. Originally I had the repeated blocks of code as a subroutine, but for reasons I don't know, it didn't want to work correctly. It was calculating the correct values, but wasn't returning them correctly. Of course, I was working on this in the evening after a day of programming, so by that time I was probably suffering from that weird sort of programming blindness where the answer to the problem is hiding in plain sight.

I'm going to incorporate your suggestions (as well as the suggestions of others) and will post the modified version as soon as it is ready. Thanks much.
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Kurt