Ability to use Pricing UOM as Secondary for Dropship

We are using Dual UOM items (Primary is CASE and Secondary POUNDS). Pricing UOM is Secondary.

When we are manually creating Purchase Order - Pricing UOM in Purchase Order defaulting as 'Secondary' (i.e., Pounds) but when we are creating Dropship Purchase Order - 'Pricing UOM defaulting as PRIMARY' and not allowing to change the Pricing UOM to secondary even when we create a change order.

Can you please help on this.

Regards

Shankar