BP Record Count

Hi all, is it possible to do a count of records in a BP? I'm trying to add this to an existing BP where we haven't previously included a 'record count' DE that auto-populates with '1' which could then be summed up.

What I'm trying to do I find the average value of a series of records i.e. Where we have a series of variations (10 in total) with a total value of 10,000 I could get a count of records, divide by total (total in a QBDE) and find the average value with a simple formula.

I can't tell if I'm missing something simple here - I can't afford to do this in a data model etc, I need to do it in Unifier itself as the required info will not be exported to dashboards/reports etc but will be used in another BP.