Assistance required in creating BRF workflow SRM 7.0

[srini_911]

Hi Experts,
I am new to SRM. I have a requirement wherein I need a create a BRF process control workflow. In high the requirement is as follows.
Once a shopping cart is saved the workflow should start and check whether the shopping cart value is greater than or equal to 1000 USD.
*Note: Step 1 and Step 2 are only applicable when the shopping cart header value is greater than or equal to 1000 USD else directed to the step 3.In other words step 1 and step 2 are optional steps whereas step 3 is mandatory step*
*If TRUE (shopping cart value greater than or equal to 1000USD).*
step 1) The first level approver need to be determined from ztable based on the cost centre of the shopping cart.
step 2) The second level approver need to be determined from ztable based on item category id of the shopping cart.
*If TRUE (shopping cart value greater than or equal to 1000USD) or FALSE (shopping cart value less than or equal to 1000USD).*
step 3) The org unit manager approval is required. Org unit manager will be determined from the ztable based on the org unit of the shopping cart. If the value of the shopping cart is greater than the manager's approval limit (determined from a ztable), the manager approves the workitem and also the workitem should go to his manager for approval. The same applies until the approval limit of the approver is greater than or equal to the shopping cart value.
In the above requirement step 3 approval levels is dynamic. Please help me in achieving this requirement.
After decission:*
In some cases the first level approver will edit the shopping cart , make some changes and will resend the same shopping cart to the requestor (the person who created the shopping cart). If the requestor admits the same changes and save the shopping cart there is no need of sending the workitem to the first level approval again, but incase if the requestor makes new changes the workitem then the workitem should go to the first level approval. The same is applicable for the second level approval aswell.
How will the requestor identify the changes done by the first level approver or second level approver?? Is there any log where the changes done by first level approver or second level approver are saved?

Thanks and Regards,
Prashanth..