Powerpivots

I am creating a power pivot data model on Equipment loan records to clients. Each transaction record has an:
Order Date - when equipment request is submitted on behalf of the client;
Delivery Date - when equipment item is delivered to client;
Collection Date - when equipment item is collected from client.
Each transaction is either a delivery or a collection. The 'Order Type Code' column determines whether a transaction is a delivery or a collection via column entry 'D' or 'C'.
I have created power pivot tables across a range of budgets for deliveries (quantities and value) and collections (quantities and value). Each record has columns for: delivery qty, delivery val, collection qty, collection value, and order value. For a collection the order value is negative.
I have created the DAX measure total formulas for quantities and values for both collections and deliveries, using the 'calculate-SUM function and the appropriate column filters. I have checked the source data to ensure formulas are correct.

When I drop the DAX measures into the pivot table, only the delivery information is correct, and the collection information is not.
In the data model diagram view, the datekey table date is linked to the delivery date as the main link; all the other dates are linked as secondary links. However if I change the datekey date to link with collection date first, and others secondary, the collection information in the pivot table becomes correct, and the delivery information wrong.

What DAX formulas do I use so that both delivery and collection information is correct in the same data model?