[A&R Feature Request] Add previous year data into variance report

Description: We love the set up of the missing data report & variance warnings- having the previous years data helps contextualize the variance/ missing item when reading the report. Can we match the variance report to this format?


Context:

The variance report is a great tool for us to find data anomalies, but I still find myself creating pivot tables from the standard export to understand the variance, and use past years data to show POs and staff involved with data entry why I think the number they entered may be incorrect or require an explanatory note.

Screenshots (if applicable):

Current report (excellent for locating variances, but still needs supplementary data to review the variances to see if the data needs corrections).


Start by locating the variance report implementation and comparing it with the existing missing data report format shown in the issue. Trace how report data is assembled, then confirm the variance report includes previous-year data while retaining its current variance warnings and matching the referenced format.

Written by the indexing model from the issue text.