You got through RQ real fast compare to drakef2000 post #914, but again you said it was your second application. So I am not sure.
drakef2000 post mentions that they were all RQed people at the test and you say that you all had the same orange color letter!
It seems to me that they might be cleaning up their old (maybe RQed) cases. And that might be one of the reasons for March slowdown.
Some suggestions about the color code: (guys correct me if needed)
Pink = Oath invitation
Yellow = Normal test invites
Blue = Interview only Invites (for 55 years old and above)
Orange = RQ ones