Tabular reports have a few limitations around the layouts and columns.  

Check out this one here - if you always have the same set of customers, you may be better off hard coding the column settings: 

There’s an idea here about page breaks on tabular reports because it doesn’t always follow the page size constraints (though this might be more along the vertical not horizonal page break): 
 

It also looks like you’re trying to do some analysis/totals in the final columns and I’ve never found a good way to do that in a tabular report (it usually has to be on the left, prior to the start of the tabular section.)