If department employees have been issued purchasing cards, does the account manager review supporting documentation for the purchase transactions?

I had for routine RM's no need for a signature from my Manager.

PO's over the amount of $100000 our CEO wanted to see, but once again I did not needed a second signature if it been for RM's.

All CAPEX related documents prior to using the PO, required signatures of the requesting Manager, VIP of Finance and the VIP/President of our facility ... later our mother company needed to approve /CAPEX related documents... therefore none of these PO's required any additional signatures. 

I don't believe that the account manager or finacials have to review the documentation of my transactions, as already my managers review permenantly review all my transactions through our Oracle system.

Financials employees only needs to review payments terms, item receipt, technical acceptance, matching the amount of the PO with invoice.

account manager review the purchase document for the feasibility study