Funds checking fails if total header amount greater than funds available

Hello Community,

Prerequisites: Budgetary control is enabled (detail level) for only one account, used Encumbrance type is Committment, User has funds available (10€)

following scenarios I'm struggling with:

1. iProcurement: User adds 4 items to cart
   • item 1, quantitiy 1, price 10, charge account 1
   • item 2, quantitiy 1, price 2, charge account 2 (under budget control)
   • item 3, quantitiy 1, price 3, charge account 2 (under budget control)
   • item 4, quantitiy 1, price 30, charge account 3
   • total header amount: 45€
   • User performs checkout > funds checking fails
2. iProcurement: User adds 4 items to cart
   • item 1, quantitiy 1, price 1, charge account 1
   • item 2, quantitiy 1, price 2, charge account 2 (under budget control)
   • item 3, quantitiy 1, price 3, charge account 2 (under budget control)
   • item 4, quantitiy 1, price 4, charge account 3