Field help (POHORDMIN) 

This amount, which cannot be accessed, is a reminder of the minimum order amount defined for the Supplier.
It is expressed in the order currency.
At the end of the order entry, the order can be subject to a control if the ex-tax amount is lower than this threshold.
The Control field displays the level of control (Block, Warning, No control) as set by the POHMINAMT - Order min amount parameter (ACH chapter, AUZ group).