Adjust Date Time - under the Edit menu does not allow consecutive adjustments.
When I use the "Adjust Date Time" under the Edit menu, it does work but if I select another picture or multiple pictures. the 'Adjust' is replaced with "Undo". Bottom line is that I can't make consecutive adjustments to the date time without quitting the Photos app and then restarting to be able to 'Adjust'.
MacBook Pro 13″, macOS 10.12