User Activity for stats - improve the report

Many clients ask us for quarterly usage reports, and we cannot generate consistent reports over time. We need a report where we see SENT assessments and assessments completed via Open Link, not completed only. We also need to know who sent BA, CA, JA . We need to count deleted and expired assessments as well, as even if not completed, they count as sent.
We need to filter down the period as well (from X to Z, current FY, last year,... like for Client User Activity report).