Hi Robert.
The Customer list report has a "static" info on Total Sales or Total visits. Meaning is reading only the Customer table, where You only have Customer generic data and accumulated sales data...
If You want to achieve this info within a specific range dates, You (or a RMS Partner) will need to modify a Sales report, probably the Detailed sales report, extend it with Customer data and keep an filter based on Transaction Date, to sum the totals and visits… It is not hard, but few hours of work is needed for sure. I would also recommend You talk to an RMS Partner to do this for you, if You are not familiar with SQL and the RMS tables...
Best regards, A.