Your logic is right but for a traveler without a detailed knowledge of the place it might be confusing...and as the person asking the question was seeking for direct connectivity to BJU I mentioned PVC Exp as it enters in a time I normally dont sleep but for 13185 its hard to wake at 3.30 considering the cool breeze from the Ganges!
As fot unofficial halts i dnt knw about HTZU but Rajendra pul has become an important station so that all trains incl Raj halts there regularly!