I agree. It could probably be streamlined. But let's look at what happens. Based on what I've read and heard (feel free to modify)
Test is at day 1.
Proctors have to account for all of the answer sheets, tests, etc., box everthing up and ship it back to NCEES. By the time NCEES gets everything, one week has passed. (My assumption).
They start running answer sheets through the scanning machines. How many? volumes of test takers is a closely guarded secret for some reason, but if I had to guess, 20,000 FE and 10,000 to 13,000 PE? So let's say 32,000 answer sheets. [EDIT - I JUST REALIZED THAT YOU HAVE AM AND PM ANSWER SHEETS - SO DOUBLE THAT TO 64,000!] I would hope that they would run them multiple times through different machines for accuracy. Including all of the kickouts that have to be looked at manually because of erasure marks or missing data or whateever, this probably takes 2 weeks. Plus I would imagine (at least I hope) that they pull a certain % to handgrade them to make sure the machines are working properly but I'll include that time in the two weeks.
Next, somebody has to start evaluating the answers to see if there are problems. I would hope that if the answer is "A" on a question but 80% of the people say "B", that someone has to look at that and determine if A or B is the correct answer. Or both. All those have to be resolved. How many are there and how long does it take? Who knows. Let's say a week. So now you have different answers to some questions. I guess you have to run all of the answer sheets back through with the revised answers. Probably multiple times again. Another 2 weeks.
So we're up to what, six weeks so far. Now they've got to determine the passing score. Based on the control questions or equating process. However that works. I bet that takes a week. Somebody has to review it and approve it for every exam (different people?) so probably another week.
So now we're up to eight weeks. Now they start coming up with all of the results and sending stuff out to the states to do their thing. That 10-12 week time frame doesn't look that far off. I guess if they don't do all of the quality control stuff that I assumed, it should be a lot shorter. Also, I'm guessing how many answer sheets there are. I didn't even think about surveying so who knows.
Fire away at my logic. Just my $0.02.