WS14500015 - changes in second approval level

Question

Hi all,
I'm fine tuning our two step item level approval workflow based on the WS14500015 standard flow. I've come across a problem which seems to be quite commonly discussed here, but I've also gotten the feeling that it may result in a catch-22 situation.
Scenario:
We're using a custom model, in which approvers are fetched based on the criteria for the items in the basket from a table and are assigned approval objects. Second level approval is based on product category, where approvers are assigned approval objects only if they are found for the particular category.
The issue arises when the second level approver alters the cart above the limits of the manager who approved in the initial level. We would like this to trigger a new chain of approvals, in which the manager responsible for the new value (or cost center) has to process the new cart from step 1, but as of now the cart is automatically approved following acceptance from the initial agent.
In general, it would be best to just not let the second level approver alter the items since he or she is not really authorized to do so, but I can't see a way of controlling this, since we can't restrict the customer from using the same manager as first and second level approver (in cases where alteration rights based on security level is concerned).
I've debugged the code, and confirmed that the objects are updated as expected, but the cart is still completely approved after a second level change.
Is it in scope to allow interlevel cart changes? Can I use the BBP_WFL_SECUR_BADI to change security level according to current approval step?
I would greatly appreciate a small summary of what is possible and what is not possible regarding this general scenario, and the recommended approach (if such exists).
Many thanks in advance!

Answer 1

as in all own implementations you should copy the sap workflow to an own one, like Siddharth proposed. I didn't try this, i never needed second level approval so take what i say with a grain of salt.  Copy the task that deals with the approval (the one showed in the UWL of the first manager) for the next approval (second manager). It should be then inserted in the workflow after the first approval. Between the original approval task and the second one you should insert a step where you call your own abap class to set the new processor of the workflow - copy the one used by SAP in the first approver task and remove what you don't need, modify the stuff that you could use.
You might be able to get the approval in the approval application using the BADI proposed by Siddharth but I am not sure using that BADI will create a UWL entry for the second approver.
@SAP: a propos the class used for workflow task methods--> stop creating final classes !