Thomas - part of our question is already answered by Guy (Guy, thanks for your help :) ) on http://forums.visokio.com/comments.php?DiscussionID=292&page=1#Item_0.

However we still are struggling with an average calculation in a specific situation. Explaining the situation gets complex easily and that's why I have attached a simple example. The main characteristic of our table is the fact that the variable for which an average is needed (Sales in the example), is equal in multiple rows. Week 1 has sales= 5 as shown on each record in column Sales. Week 2 has sales=4. The average over the two weeks is 4+5/2=4,5.

When calculating the average by using Aggregate (aggregate on shop and set Sales to Mean), Omniscope gives 4,67. This is to be expected as week 1 has 4 records and week only 2. This is clearly not the correct method in this situation.

Column AverageCalculation contains a formulae we defined that calculates the correct value.

Our question is: is there an easier way of doing this? Is there functionality we might have missed?
As the formulae has a negative impact on performance, we prefer an easier way.

Thanks for your help!
Arjan