Norma, I encourage you to lengthen the time of your proofing to see if blisters appear. I bet they do. I usually don't proof for more than 6-7 hours though. It really depends on how much yeast is in the dough. I guess some doughs won't tolerate a 6hour+ proof. I also usually only allow the doughballs to proof that long if they look like they are handling it ok. If they start to look like they are getting tired or show any signs of deflation, I'll start the oven.
I looked back at the 2 recipes for the first pie in this thread and the recent one to compare and try to find the difference for the darker color. Though they are 2 different recipes, they are rather similar. The difference being that the first pie contained a small amount of sugar 1.2% per 290gm dough (or 1/2 tsp). That could account for the browning.
I've also been known to use a mixture of a variety of locally available flours (some bleached and others unbleached) and that may account for some of the color differences. My recent tests involve a 50/50 blend of AP&BF.
To make matters even more confusing, I also frequently test varying oven/rack setups to try and optimize my pizza bake. This too can account for more or less crust coloration.
As I am slowly improving, hopefully I can cut down on the number of variables and better pinpoint the source of different outcomes.
I hope to have more pimped pies this coming week.