As a Marketer I want to be able to group opens and clicks for transactional mails based on the sending date (in the defined reporting period) instead of the start date so that I get actual rates and unique KPIs by date resulting in a more accurate analysis of the KPIs over time.

Campaign's current solution does only allow to group based on a starting date. For transactional messages this results in two major disadvantages if you want to check the performance over time (by selecting grouping by date):

1) Data of unique opens and unique clicks are higher because they are only unique on the basis of the day. This means that one recipient who opened yesterday and today will result in two unique opens (yet, one unique would be correct).

2) There is no clear connection between mailing and send date. This means that you cannot see if the opens/clicks are made in the transactional mail from yesterday or the one from three months ago.