Why not simply using ?

ActiveWorkbook.Sheets("INV ACC")Range("D15:I214").copy Workbooks("Centris Periods.xlsm").Sheets("sheet" & [navigation!G12]).Range("D15")
or

Workbooks("Centris Periods.xlsm").Sheets("sheet" &  [navigation!G12]).Range("D15:I214")=ActiveWorkbook.Sheets("INV ACC")Range("D15:I214").value