How to display grade from prior salary change on same line

Summary

In a comp history analysis, I need to report on employee's grade as of the salary update immediately prior to the current salary

Content

Subject Area: Compensation - Salary History Details Real Time

I have a priority request to report on all salary increases within a certain date range. The executive would like to see current and prior compensation details as of each salary change date. There's a convenient field "Prior Salary" to report on the salary immediately before the current, but I don't see anything like that for prior grade. The request is really to compare grade-specific fields (such as bonus target) for the current and prior salary change. But I figure if I can at least get the prior grade name itself, I can manually merge in the rest of the