Hi Steven
I agree it's a bit odd (as move/copy body has this ability-see edit). However you could use a Linear Sketch Pattern Instead.
The workflow would be slightly different, here I added a fixed constraint on the corner of the first instance, but this could just be coincident to any point. It's a flexible technique as there are lots of ways to control it. eg add a constraint to the last instance or delete the pattern relation and make everything free.
edit:
Try changing the parameters to "X/Y"