You are absolutely correct.
You could use the direction editing feature to have the cursor stay on a step longer than 1/16 note. In fact it may stay there up to 9/16 of a note, in 1/16 intervals.
In the current implementation however, it would trigger an active note on that step every 1/16. In your scenario, if step 5 is active, it will just be played 4 times (4/16).