Here you have a sample coding  if the implementation has to support multiple steps with BADI as agent determination rule and each step has pre-conditions.  


DATA:
  ls_badi_approver     TYPE if_mmpur_workflow_agents_v2=>bd_mmpur_s_badi_approver,
  lt_badi_approver     TYPE if_mmpur_workflow_agents_v2=>bd_mmpur_t_badi_approver,
  ls_previous_approver TYPE if_mmpur_workflow_agents_v2=>bd_mmpur_s_previous_approver,
  ls_new_approver      TYPE if_mmpur_workflow_agents_v2=>bd_mmpur_s_badi_approver.

DATA: lv_costcentre    TYPE string.
** define the list of BADI approvers
**  -----  Approval Level 1 -------**
* Level 1 is based on net price.
if previousapproverlist is initial.
SELECT SINGLE PurchaseRequisitionPrice, PurReqnItemCurrency FROM I_PurchaseRequisition_Api01 INTO @data(ls_item)
WHERE purchaserequisition = @purchasingdocument and PurchaseRequisitionItem = @purchasingdocumentitem.
    if  ls_item-PurchaseRequisitionPrice > 500  and ls_item-PurReqnItemCurrency EQ 'EUR'.
    ls_badi_approver-businessuser = 'CB9980000658'.  " WF_MGR2 is the first level approver.
    ls_badi_approver-approvallevel = 1.
    APPEND ls_badi_approver TO lt_badi_approver.
    ls_badi_approver-businessuser = 'CB9980000009'.  " Administrator is another approver at same level.
    ls_badi_approver-approvallevel = 1.
    APPEND ls_badi_approver TO lt_badi_approver.
    Endif.
endif.
* Level 2 is based on account assignment category.
if lt_badi_approver is initial.
SELECT SINGLE AccountAssignmentCategory FROM I_PurchaseRequisition_Api01 INTO @data(lv_acccat)
    WHERE purchaserequisition = @purchasingdocument.

If lv_acccat EQ 'K' AND NOT ( line_exists( previousapproverlist[ businessuser = 'CB9980000659' ] ) ).
    ls_badi_approver-businessuser = 'CB9980000659'. "WF_VP1 is second level approver.
    if ( line_exists( previousapproverlist[ businessuser = 'CB9980000658' ] ) ).
    ls_badi_approver-approvallevel = 2.
    else.
    ls_badi_approver-approvallevel = 1.
    endif.
    APPEND ls_badi_approver TO lt_badi_approver.
Endif.
Endif.
* Level 3 is based on Material Group.
if lt_badi_approver is initial.
SELECT SINGLE MaterialGroup FROM I_PurchaseRequisition_Api01 INTO @data(lv_matcat)
    WHERE purchaserequisition = @purchasingdocument.

If lv_matcat EQ 'A002' AND NOT ( line_exists( previousapproverlist[ businessuser = 'CB9980000656' ] ) ).
    ls_badi_approver-businessuser ='CB9980000656'. "i044736 is third level approver.
    If ( line_exists( previousapproverlist[ businessuser = 'CB9980000659' ] ) ).
    ls_badi_approver-approvallevel = 3.
    elseif ( line_exists( previousapproverlist[ businessuser = 'CB9980000658' ] ) ).
    ls_badi_approver-approvallevel = 2.
    elseif previousapproverlist is initial.
    ls_badi_approver-approvallevel = 1.
    endif.

    APPEND ls_badi_approver TO lt_badi_approver.
Endif.
endif.
* Level 4 is based on Creation Indicator.
if lt_badi_approver is initial.
SELECT SINGLE PurReqnOrigin FROM I_PurchaseRequisition_Api01 INTO @data(lv_prorigin)
    WHERE purchaserequisition = @purchasingdocument.

If lv_prorigin EQ 'S' AND NOT ( line_exists( previousapproverlist[ businessuser = 'CB9980000656' ] ) ).
   ls_badi_approver-businessuser = 'CB9980000657'. "WF_EMP1 is fourth level approver.
  if ( line_exists( previousapproverlist[ businessuser = 'CB9980000656' ] ) ).
   ls_badi_approver-approvallevel = 4.
   elseif ( line_exists( previousapproverlist[ businessuser = 'CB9980000659' ] ) ).
    ls_badi_approver-approvallevel = 3.
    elseif ( line_exists( previousapproverlist[ businessuser = 'CB9980000658' ] ) ).
    ls_badi_approver-approvallevel = 2.
    elseif previousapproverlist is initial.
    ls_badi_approver-approvallevel = 1.
    endif.
    APPEND ls_badi_approver TO lt_badi_approver.
Endif.
Endif.
**  remove the previous approvers from the list of BAdI approvers.
LOOP AT previousapproverlist INTO ls_previous_approver.
  READ TABLE lt_badi_approver INTO ls_badi_approver
      WITH KEY businessuser = ls_previous_approver-businessuser.
         CHECK sy-subrc = 0.
      DELETE lt_badi_approver WHERE approvallevel = ls_badi_approver-approvallevel.
ENDLOOP.

**  determine the next approval level and appropriate approvers
READ TABLE lt_badi_approver INTO ls_badi_approver INDEX 1.
LOOP AT lt_badi_approver INTO ls_new_approver
        WHERE approvallevel = ls_badi_approver-approvallevel.
        APPEND ls_new_approver-businessuser TO approverlist.
ENDLOOP.