Difference between cancelling a PO using buyer's workbench vs Add/Update POs page

What is the difference between cancelling a PO using buyer's workbench vs Add/Update POs page?

From what's I've found so far: 

Using Buyer's workbench

-Can still view the PO with status of pending cancel in Add/Update POs page

-After budget checking and dispatch, the PO hdr status changes back to Dispatched.

-PO Lines are cancelled

Using Cancel button on PO page (red triangle)

- Have the option to resource requisition

- PO can only be viewed under 'Review PO Information' with status pending cancel

- After Dispatched, PO hdr status changed to Cancelled

- All PO lines cancelled

I'm not sure whether it is a bug or working as designed for the PO status to change back to Dispatched when cancelling from the buyer's workbench.