Development Months Range

{Range(
    OpeningElement([Date].[Development Month]),
    Lead(
        OpeningElement([Date].[Development Month]),
        [measures].+[fb104c35-107a-40fd-9530-d408980a185c]+11
    )
)}

Underwriting Year Range

{Range(
    OpeningElement([Date].[Underwriting Year]),
    StrToMember(
        [Date].[Underwriting Year],
         ToString(
            [measures].+[f544516d-8e80-421a-9375-8b60bb6a65ce]
        )
    )
)}

Layout Cumulative Premium

CASE(
    [measures].[Facts Cumulative Premium]=NULL,
    0,

	ConvertToNumber([Date].[Development Month].currentmember.caption) > ([measures].+[fb104c35-107a-40fd-9530-d408980a185c])
	&& 
	ConvertToNumber([Date].[Underwriting Year].currentmember.caption) = ([measures].+[f544516d-8e80-421a-9375-8b60bb6a65ce]),
    null,

    ConvertToNumber([Date].[Development Month].currentmember.caption) = ([measures].+[fb104c35-107a-40fd-9530-d408980a185c])
    && 
	ConvertToNumber([Date].[Underwriting Year].currentmember.caption) = ([measures].+[f544516d-8e80-421a-9375-8b60bb6a65ce]),
    AGGREGATE(
        MTD(
            LAG(
                [Facts].[Entered Date].@[7f25f5e1-d1aa-4916-9d01-1f336e519b23],1)
           ),
           [measures].[Facts Premium]) 
	+
    AGGREGATE(
        RANGE(
            OpeningElement([Date].[Development Month]),
            LAG([Date].[Development Month],1)
       		 ),
        [measures].[Facts Premium])
    ,

     [measures].[Facts Cumulative Premium]

)