Yes, those are the kinds of gains we see with folks using proper training. We know that it is counter intuitive that you can go faster but training easier. But all it takes is for you to do a workout like this to make a believer of you. The gains don’t come in a steady or uniform way they tend to come in fits and starts where one day you have breakthrough workout that tells you are indeed fitter than you used to be. Just saying this so you do not expect to see these kinds of gain every day or even every week.
Great job and my guess is that you have just begun to scratch the surface.