Ok. So I fixed this by exporting and reimporting the corrected values on the three affected items, then doing an adjustment against the control account to wash the dr and cr to bring the total valuation down. For the record, two items were 100x and one was 10,000x the correct amounts in cost, history, and the calculated fields. Thankfully it was only three items, and thankfully, Adagio has the flexibility to fix this without having to do a full data restore.
Thanks for your input. Greatly appreciated.