Sounds to me like a good use for a web bot. Use LWP or LWP::Mechanize (depending on how much of that you want to write yourself) to get the pages, HTML::TokeParser::Simple or HTML::TableExtract (depending how flexible you need to be) to get the utilization numbers from the tables, and Spreadsheet::WriteExcel or Win32::OLE (depending whether you can write new or need to update existing) for the spreadsheets.
Good luck,
Ben