Sales Order Measure in Demand Management does not match Manage Shipment Lines Open Orders

We have run collections and Demand Plan with refresh with current data. However, in various scenarios when looking at Sales order measure in a table the value shown in the bucket for May (our testing) does not match what is shown in the export of Shipment Lines that have not been shipped.

For example, Item G007550, in our Demand Plan table shows Sales Order value as 19, but there are 20 in the export.

Screenshots were removed for data security *

As another example, we see item G007507, showing as 38 Sales Orders but only 27 on the Shipment Lines Export.

Any idea what might be causing this mismatch? We have reviewed the following as well: