When we were at PO-R, PO-FQ was closed. But when we were last at PO-FQ (albeit 11 years ago) the bus did come to FQ first before PO-R. Several times people were not able to get on the bus. And the ones who did were mostly standing. This may have changed, but from what I've read on these boards, it hasn't.
Last year while at PO-R, we always walked to the main bus stop. We were in the Mansion buildings, but from what we experienced on our previous trip, the satellite bus stops were often not serviced (buses too full). This was true again last year. We would board out front, and if we weren't full at the main bus stop, we were certainly full by the first satellite stop. I felt sorry for the people at the 4 bus stop. You could see the frustration on their faces.
My recommendation: If you stay at PO-R, go to the main bus stop. If you find that the buses are constantly full, walk to the PO-FQ and pick it up there.
Hope that helps.