Refresh Population runs and complete but no effect on the promotion

Hi,

I've created a promotion with date range as below, and entered 1000 units into an override series.

ship start:  15-JAN-17                           Note: event start: 22-JAN-17

ship end:    04-FEB-17                                     event end: 11-FEB-17

When I created a promotion all the 1000 units are allocated between the ship start(15th jan) and ship end date(29th jan). Ours is Sunday time bucket.

Then the same promotion has been modified as below,

ship start: 29-JAN-17

ship end: 12-FEB-17

After the modification, all the 1000 units shifted to 22-JAN-17 and 05-FEB-17.

As per my expectation, it should shift to new ship start and end date. For that i've created refresh population method and workflow and invoked that method on the created promotion.