Calibre scrambles subject tags sequence

I want to create a mobi from an epub for upload to Amazon Kindle. When I load the epub, Calibre changes the sequence of the metadata genre subjects. It shows them in alphabetical order in the metadata screen but sequenced with no apparent reasoning in the raw code. I want to keep the subject sequence I have in the ePub content.opf metadata code.

I have the latest versions for Windows of Calibre, ePubChecker, and Kindle Previewer. I am running Win XP SP3.

I have searched the FAQs and the web for this issue with no joy.

Thanks, Bob