Pricing rule is working when we change the total quantity of default unit of measurement. But if we change unit to any other one specified in item, pricing rule will not apply.
Refer the below snapshots. Added pricing for 5% discount for sales more than 10-30 pieces.
Added another UOM box with 10 as unit of fraction.
When i select box as UOM with 2 quantity, pricing rule is not applying. But when i give 20 as quantity with unit Nos pricing is working perfectly.