Ph uses a different map vote. The cool down issue is being looked into and is mentioned in the suggested thread for PH. From my understand it seems to favor the maps played a lot for some reason. What’s nice about ph is it keeps track of how many times the map has been played. My suggestion would be to look at those numbers and if a map is played x% more of the time, it corresponds to a y% lower odds of showing up in the map vote.
If you look on game tracker comparing PH to TTT, ph plays the 5 most popular maps 10-15% more of the time than TTT
If you look on game tracker comparing PH to TTT, ph plays the 5 most popular maps 10-15% more of the time than TTT