This sounds like something we would say. If we were having you track your dropped calls in preparation for a trouble ticket, we generally suggest either *** or ###. To be honest with you, it doesn't really matter what you use as long as you remember what you have marked it with. When we file the tickets, and the engineers look at them, they will generally see our notes that say something along the lines of "Customer marked problematic calls with ***/###." When they look at your records, they will look for those calls and track the call just prior to the ***/### call.
Hope that answers your question. Let us know if you have any other questions.