How do you want this to work?
I imagine it would work something like the following:

1. The filters would be used to select the products to update.
2. Matching products would be displayed in a table.
3. This table would be pageable if there are too many matching products.
4. Fixed and unit prices would be directly editable in the table.
5. Changing a price creates a new price version, if the price existing price has been saved.
6. Modified prices would be highlighted (e.g. cell background colour change), until saved
7. Historical prices would be visible in dropdowns made visible by clicking the corresponding fixed/unit price cell
8. Changing a price back to its original value (either by direct entry, selecting a historical price from a dropdown etc) would remove the 'modified' highlight.
9. Beneath the table, would be the fields to enter batch fixed and unit price modifiers.
10. An Apply button would apply the batch fixed/unit price changes to all products matching the filter
11. Pressing Apply would update the prices displayed in the table
12. Applying more than once without saving would not add create multiple price versions
13. A Save button would save the changes
14. A Revert button would revert all unsaved changes
15. A Print button would print the current products being updated
16. If other users are editing products while price changes are being performed, versioning issues may arise. Rather than aborting the edit, those products that can't be saved will be displayed in a dialog with the current version displayed. The user will be given the option to apply their price update, or skip it, for each conflict.

-Tim