I think 1.5 hours should be closer to the right cook time too. This could vary a bit, but not a full extra hour. I recently switched to Royal Oak briquettes from Kingsford (the suggested brand of PBC) in the PBC. It makes the charcoal flavor a little more subtle than the Kingsford does. It seems to cook food in the same amount of time for me and the start times are the same. Also, I use a pretty large amount of lighter fluid. It is a ton of charcoal in there.
I use a full basket of charcoal, I use the lighter fluid method, and I let it go for 20 minutes before placing the meat. I have this part down to a science and don't alter it in any way. Also, I only open the lid once. That's to flip meat on the grate halfway through. This step is not necessary as it will cook evenly without flipping, but the very subtle grill marks created help with the presentation to others (I do have an exception when making wings, where I will baste and cook on an open flame the last 5-10 minutes).