Put the current budget balance beside a purchase request for review.
Add budget figures and source links to purchase requests.
Your finance reviewer can see the current budget balance beside a purchase request, without hunting through a separate sheet.
Update purchase requests awaiting approval with revised balances.
Your pending purchase requests show revised balances beside the amount requested, giving finance reviewers the latest sheet figure as they decide.
Add current budget balances to pending purchase discussions.
Your reviewers can see a current budget balance beside pending purchases before deciding, with a fresh note when the figure changes.