DAX Measure For Calculating Stocking Levels

Hey,

I created your table in Excel in Power BI. Above it slicers for the parameters. You can use the following code to calculate 'Tier 1':

Tier 1 = 
VAR _ProposedCS =
    SELECTEDVALUE ( ProposedCS[ProposedCS] )
VAR _PropesedLT =
    SELECTEDVALUE ( ProposedLT[ProposedLT] )
VAR _AnnualUsage =
    SELECTEDVALUE ( 'Table'[Annual Usage] )
VAR _TT =
    SELECTEDVALUE ( 'Table'[TTQ] )
RETURN
    IF (
        _ProposedCS * _AnnualUsage > 5,
        VAR _m1 =
            MAXX (
                {
                    _TT + _TT - 1,
                    ROUNDUP ( DIVIDE ( _ProposedCS * _AnnualUsage, 12 ), 0 )
                },
                [Value]
            )
        VAR _m2 =
            ROUNDUP ( DIVIDE ( _ProposedCS * _AnnualUsage, 365 ) * _PropesedLT, 0 )
        RETURN
            _m1 + _m2,
        0
    )

You can use the above code as a basis for calculating the other calculations. Adjust the parameters and conditions for this. Hope this helps.