PO release strategy - Can creator of a PO, be an approver?

Hello All,

I have a following example:

User1 is a buyer who can create PO's

User2 is a buyer as well as 1st Level Approver/

User3 is a final approver of the PO's

Assumptions:

Stand. PO Type

PO value under $100 can be approved by User2

PO value above $100 should be approved by user2 as a Pre-requisite and Final Approval can be done by User3.

Release Strategy is at PO Header Level

Question1:If user2 creates a PO under $100, then user 2 Cannot approve his own PO and must trigger a Final Approval (next level release) by User3. Can this be achieved.

Question2:On Rejecting a PO, where to put some text for Rejection?

Thanks