According to NCARB's website, Prometric recently experienced some scoring delays related to the new ARE 4.0. I am hoping these kinks are worked out now and it will not take more than two months to grade each of the other tests. Perhaps by the time I take my fourth test in mid-January, I will know whether I passed the other two I have already taken.
Before I started taking my tests, several of my recently-licensed friends advised me to set a pretty steady test-taking schedule and stick to it. I have been successful so far in sticking to my one-test-a-month schedule so far, and with continued perseverance (and passing grades!) I will complete all my tests by April!