Hi, As long as Planual recommends to not hardcode any values directly in the formulas and make the calculation scalable, the best way would be to get the Mean calculated properly first. Do it on a separate line item with required dimensions only. If you always need Mean be calculated as a sum of 6 months, then as said earlier - you do not need the timescale for calc. Do that 6 months sum once and consider that a fixed value to linked to any certain month for further reference If Mean should be calculated differently for every month within a year and you know the exact rule on how to calc it - use timescale as a dimension and design the scalable formula for calculation. For example you can get values for only actualised months via IF formula and put 0 for all remaining periods. In a next step you can refer SELECT: TIME.ALL PERIODS or SELECT: TIME.YTD to get the sum of all actualised periods and use that value as a denominator in you original calculation. There are also some different techniques available if you work within few years - to use LOOKUP by Year for example, but I hope something simple can work in your case
... View more