Excel Chart Formatting Problem

I'm having problems with charts not keeping their format. I have an excel sheet workbook that needs to be updated every year. This update process involves making a copy of the previous year's workbook. So because of this most of the sheets are exact replicas. The only difference being that the chart and pivot table data source changes from last year's massive data table to this year's massive data table. The only thing that really needs to be changed is the pivot table data source and the chart data source. The chart data source is each of the individual pivot tables that are created from the main data table. My problem is that when I try to update each chart the format changes entirely. I have tried the "Properties follow chart data point for current workbook", but it doesn't preserve the format of last year's charts either. Any ideas?

Thanks