Excel-Sum()-Function gives weird values, 1904-Calendar format

Topics: Developer Forum, User Forum
Feb 4 at 1:36 PM

I am trying to build a simple timesheet. At the moment I have several issues.
Code and xlsx: https://phpexcel.codeplex.com/workitem/22160

1) How to set the 1904-calendar-format with the 2007-writer?
2) The SUM()-results are wrong! Why does it not work? If I create the document manally it works fine so I think PHPExcel has a issue.

Thanks for any help in advance!