A couple of things that come to mind....
1. I'm pretty sure that taking the time to unwrap, then quench caused a lack of hardening. What a lot of folks don't realize is that the recommended "austinizing" temps for steels means that the steel needs to be AT THAT TEMP WHEN IT HITS THE QUENCH.
Generally speaking, in order for a carbon/plain steel blade to fully harden, it must go from its austinizing temp, to 400F or less, in 6 seconds or less.
I once visited with a fella on the phone for over an hour, trying to help him with steel that "wouldn't harden".....I finally asked him to take me step by step through his procedure....when he got to "I take it out of the forge and WALK to the quench tank..." (RED FLAG) I asked him where his quench tank was in relationship to his forge..... "about 15 feet away" was the response. He said he was heating to 1550F, then taking the blade(s) out of the forge and to the quench tank. I'm sure his blades dropped below austinizing temp in that distance. Again... the steel must be at its austinizing temp WHEN IT HITS THE QUNECH MEDIA. We solved his whole issue by him moving the quench tank next to his forge....where all he had to do was remove the blade from the forge, and simply turn 90 degrees to get it in the quench.
2. Personally I think the temp you're using it a bit too low. Nearly all of the damscus I produce is 1084/15N20, and I always take it to 1550F for the quench, then temper 3X for 2 hrs each at 415F. Everything we do in knifemaking has a level of "give-n-take" to it.....in this case I go slightly above the austinizing temps of SOME carbon steels. I risked some slight grain growth by doing so, but in return I ensure a blade is at its austinizing temp when it hits the quench.
3. Soaking: Although you hear about it a great deal these days in many "knife" circles, I totally disagree with soaking any carbon steel at or beyond its austinizing temp. With plain carbon steels, any temp in excess of the austinizing temp causes grain growth at a expodential rate. Many people use this "trade off" to achieve Rc numbers that they feel are impressive, when in reality it causes more harm then good through increased grain size, which manifests itself in a number of different way in the finished blade...... this could be displayed in difficulty sharpening, a lack of edge retention,the edge being "chippy" in a fine cross section, and/or a more fragile blade then one would achieve without the soaking.
OK, all that being said, there will come a time when you simply run out of "chances" when it comes to hardening/heat treating. If you get to a point where you keep seeing lower and lower Rc numbers, its a good bet that you've reached the limit and its time to start on a new blade. Personally, the limit I've set myself is twice......it I don't get it in two tries, I start over.
Finally, don't let yourself get hung up on Rc numbers. While they are a "feel good" sorta thing, and they can provide valuable insight to a knifemaker. they are something to be "used" rather then "highly sought". To put it in perspective, I've seen many well designed/executed blades over the years that only went Rc 54-58, that would far out perform poorly designed and executed blades with Rc hardness levels in the lower 60s.
The best thing to do is use the situations you've encountered as learning tools. When you come to a result that is less then what you anticipated/expected, walk backwards through the process you used and try to pinpoint possible causes of you not achieving what you expected/anticipated, then evaluate each of those steps and determine what you could or should do differently to achieve your desired outcome, that is one of the things that most long term knifemakers share.....learning to evaluate and correct possible "flaws" in thier procedures, and understanding that we are all in a constant state of learning.
Keep us posted!