Converting MDX query into SSAS cube expression [Calculations]

Question

How can I go around to amending this MDX query

WITH MEMBER [Measures].[PanelSoldMonthsPre] 
AS ' [In Charge Date].[In Charge Date Days in Month].CURRENTMEMBER.membervalue'

MEMBER [Measures].PanelSoldMonths 
AS [Measures].[Panel Sold Days] / [Measures].[PanelSoldMonthsPre]
     
SELECT
    [Measures].[Panel Sold Days], [Measures].PanelSoldMonths} ON COLUMNS,
NON EMPTY
    ([In Charge Date].[In Charge Year].Children,  [In Charge Date].[In Charge Date Days in Month].Children) ON ROWS
    FROM [Cube]

to..

a) bring back Year Month and corresponding number of days in month. At the moment its returning just the unique [In Charge Date Days In Months].

I want it to return the [In Charge Date Days In Months] for all 12 months for each [In Charge Date].[In Charge Year]

b) placing it as an expression in the calculations (calculated measures) section of the cube project. I decided to create them as 2 separate members. Clearly does not work since I get a return of [Measures].[PanelSoldMonthsPre] '#VALUE!' on the cube (excel workbook)