Excel 2007 creates huge 97-2003 versions of spreadsheets

Hello All,

have discovered a pattern in Excel 2007. For compatibility reasons, spreadsheets have to be saved in the 97-2003 format. But when done, a simple, small spreadsheet (a few columns/rows, no calcs) goes from being a couple hundred kb to 8MB or larger.

Anyone else heard of this?
thanks….