Hrmm... this is a good point. In the past, we have encountered issues with not rounding the cursor before counting positions, but generally those are a result of using an arbitrary range (e.g., SelectionController.selectRange). In **theory** it should not be necessary here, however, I do not yet have enough proof to feel completely comfortable removing it. It is effectively a slightly expensive no-op if the cursor is always in on a valid step, so there are no harmful side-effects from leaving it.

For this PR, I would like to leave it in as "better safe than sorry". I've added a TODO to investigate this further, and plan to do so using Bella's help. Is that acceptable to you? :)