Exporting file to 64-bit Excel 2013

Does anybody use 64-bit Excel 2013? A client in Canada was having issues after exporting a block model to Excel: they were unable to perform calculations on the spreadsheet as all of the numbers were stored as text. The numeric columns in the file are stored as numeric values (real, float, and long), so it's not a problem there. I exported the file to 32-bit Excel 2013 as an XLSX and XLS and all columns were formatted as General, allowing any calculations to be performed. Does anyone use 64-bit Excel 2013 and can test this behaviour?