Excel macro on CRM report output

I have exported a CRM report to Excel and written a macro in Excel to do some calculations etc. based on field values.  When I run the macro, all the columns from the report output shift to the right beyond the columns I've added in my macro, so the calculations I've included in the macro result in 0.

I have not yet learned SSRS report writing so I was hoping a macro in excel would be a stop-gap for this.  Can excel macros be used on CRM report output?

Thanks in advance!