Build 3.0.0.144 of xlsgen adds support for special number formats such as "#,".

When a number format ends with one or more thousand separators, Excel will actually divide the number being formatted by a thousand, a million, and so on. So 12345 formatted using "#," becomes 12. And 12500 formatted using "#," becomes 13, meaning that Excel also rounds it up.

xlsgen mimics exactly this behavior.