travger, thanks for the explanation. Now the way you're doing it makes a lot more sense to me.
If I use one format quality rating tag at record level, I can assume it applies to my "preferred" calibre format (epub), if that "preferred" format is there. If not, I can assume it applies to the mobi, if that format is there. Since those two are my primary formats for iPad and Kindle. If neither is there, it's probably a pdf I had good reasons not to convert (such as complex graphics or layouts) so I can assume it applies to the pdf. That one format quality rating tag at record level works in more than 80% of my cases, possibly closer to 99%. So it's good, thank you again.
