OK, what repeats actually depends on which sync service you're using. On both the Due Today and ToodleDo sync service, when you mark the task complete, a new task will be created with the appropriate start and due date based on the repeating schedule. If you use the Due Today sync service or no sync service at all, the reminder will be repeated as well. ToodleDo does not do this for some reason (per ToodleDo's developer documentation it's best to let them handle the repeat and they don't repeat the reminder).
It's little restrictions like this that made me create my own sync service.
Just one more clarification, the "appropriate date" for the start and due dates depend on what you have selected in the repeat options. If you have "when completed" checked it will add one week to the current date and set the due and start dates that way. If that option is unchecked then it will add one week to the current start and due dates.
So, for example, if you have the start date and due set to 3/1 (per your example), then if you have "when completed" checked, and you complete the task today, the next task will be created on 3/14 (since today is 3/7). If you leave "when completed" unchecked, then it will create the new task on 3/8, which is one week from the start and due date.
I hope that makes sense.