If I change the QVD filename to something that can be created on my PC, I get exactly the same data as in the object on the only sheet. 3 rows with a NULL value and three rows with a value 1. Just the order is different. All boxes-linked lines are placed at the end of the QVD. See attachment.
%UOM is one of the fields exists in both tables you join on. That means that it will be used to match the records of the two tables. So only the records with 'boxes' as value in %UOM get a value for Expected Hours Calculation Method.
Edit: I see the same thing using Qeye when looking directly at the qvd file. However if I load it (with qualify *) I do see values for Expected Hours Calculation Method for the 'boxes' records. Could be a bug in Qeye. Qviewer does show the correct values.