it seems that phs in this zone spawn a little faster than normal mob. maybe 2-3 mins faster. using that info I figured out the 3 phs. When you cone down from the main floor into the circle, if you head south, the first cell on the left( inner) is a ph. its where I got him all 4 times for my 4 toons. heading north from there ( clockwise), you skip the next cell and the following cell on the inner side is also a ph. then continuing north skip another cell and get another ph following - which is the one marked currently on the map posted on nov 28th byRaius. I will get the locations next time I am in chapterhouse.