To paraphrase the words of the great Dirty Harry, "In all the excitement, I've forgotten whether I've turned the knob 3 times or was it 4? Do you feel lucky, punk?" While I have done it on short runs that I just "had" to get done quickly, I was very careful and visually checked powder column height in each case after filling. You have to decide for yourself what your safety practices need to be, but as a matter of SOP, I don't like multiple dumps. JMHO, of course, and YMMV.
Regards,
Froggie