The "priceDefinition" property for orders in the "chain" level in a multilevel marketplace isn't following the "sellingPrice" as expected. Instead, it's following the "price" property.

Create an order with a discount applied since the marketplace layer (level 1), in relation to the seller layer (chain, level 2), in a multilevel relationship. The fulfillment layer (level 3) will present the values correctly, but the "chain" won't.

Avoid using the "priceDefinition" property in these type of orders and do the maths using the price, quantity, unitMultiplier, and priceTag properties – to avoid issues with the "sellingPrice", which isn't a precise value.