Granted this was v2015, but I added the UDF to PO_ReceiptTierDistribution, PO_ReturnTierDistribution, PO_ReceiptOfGoodsInvoiceWrk, PO_ReturnOfGoodsRegisterWrk, and PO_ReceiptHistoryLotSerial - in addition to a IM, SO, and RMA. Then I added the UDF to CI_CommonEntry.M4L dDistribute panel (Grid Definition GD_GRID) for POReceiptTierDistribution, SOInvoiceTierDistribution, IMTierDistribution and RAReceiptTierDistribution.