My current worksheet is large but I am only particularly concerned with two columns of information (Regions) and (Days).
Depending on volume of data and indeed calcs to be performed it may be that SUMPRODUCT / Arrays will prove costly in terms of the overall performance of your file - if that becomes a reality then let us know and we can investigate other methods... if your conditional calcs are few and far between then a SUMPRODUCT based approach is certainly an excellent option.