NestedClippingDrawing doesn't quite follow Spacing & Width

Trying to understand NestedClippingDrawing specifically the Spacing & Width options. They seem to sort of follow the params, but not quite, and if they don’t fully work then this tool doesn’t work at all because I would have to go through and move ~200 pieces, which makes it unusable to me. If I understand correctly, spacing should be the distance between parts and width, when arrangement is set to WorldX, means how far over on the X asix before it makes a new row. Spacing doesn’t seem to follow at all, and width gets close. For example, if I set width to 48, then the first row will often, but not always, fall within 48", but by row 2 or 3 it’s way outside. Am I doing something wrong, or is this a bug? Also, it would be nice to group the label to the object. Then I could at least do some nesting after the fact.