There are some t13 farm parties in PF. I see like 1 or 2 a day. I see lots of t10-12 farm groups all the time. Normally around that time, you will see 7-15 random PF groups up. It is pretty active around that time almost every day with the weekends obviously being more busy then. A lot of the groups that are farming t13 are farming it in their FCs but like I said, you should catch one or two every other day.