Setting a course around the cans.....

I see diagrams like this in a few SIs. In RRS appendix L it provides some text for stating which marks are rounding marks. Unless the SI state that all marks are rounding marks then the fact the lines aren't continuous leaves some ambiguity. 

But the text at the top does say mark ROUNDING order, not passing order. Maybe that's enough to state clearly that all marks are rounding marks, rather than just standard marks. The text describing the passing order of marks doesn't state which side to round them on, and the diagram only shows one laps, so you have to infer that they should be rounded the same way each time.