I only start with 10 to 15 briquettes. A 1/4 chimney full, especially if using the large weber brand one, will yield too hot of a temp when they are completely ashed over. Next time try only 10 or 12 briquettes and see if that helps. Works great for me. Also, I've learned that the PBC is a cooker that likes to heat up but not cool down and since their is no effective way to control intake, the temps depends a lot on how hot your starting fire is aka how many lit briquettes you start with.
18.5" OTS, 22.5" OTG, CB Silver(Rip), Vintage Coleman Bullet, Pit Barrel, UDS