Why will the parts list not group items that I name manually?

Why will the parts list not group items that I name manually?

If you are using a manual numbering system like (DV1 (for directional valve), CV1 (for check valve) and so on). You will not be able to group them in the Parts list!

For grouping two or more components in the parts list, the names need to be the same (like 1A and 1B or 1-1 and 1-2). In this case, the parts list calls out component 1 with quantity 2 in one line.