There should not be a loss of hardness, but an increase in strain effects from the faster quench. These effects will manifest themselves in possible fracture and an increase in distortion problems. I just had a conversation with another mastersmith to fine tune his heat treating regimen and he was using temps that could give some of the same issues, and my answer on the topic was that if he was not having fracture/distortion issues, good for him and keep doing it until he does. But then there are the possible invisible effects of such strain. In plate martensitic systems there could be an increase in plate microfractures due to high angle impingement. But once again, if there are no overt signs of such issues can one just be happy and go with it? One thing that I must note is that often when things that shouldn't work so well are seemingly working often something else that is not quite right is making that possible. For example I have seen folks who have quenched steels in water that should not tolerate it at all, but in almost every case they are under-austenitizing in order to accomplish it; of course a medium carbon steel will survive such a quench, and that is essentially what you have when you deprive a high carbon steel of full solution. In every case when I got the proper solution that would give me full hardness in O-1 with a medium speed oil, I got distortion or fracturing in something like Parks #50.
Then you have the given properties for the intended application. A fine slicing knife can still excel in abrasion resistance and edge stability with the aforementioned issues, but impact toughness will not be the same in a steel with those strain issues. so you may never notice it in your skinner or kitchen knife, but you will in your camp knife or machete, whereas if you under-austenitize to accommodate for in inappropriate quenchant your machete may be tougher, yet need more sharpening, but you chefs knife wont hold near the edge it should.
Heating most oils will increase the heat extraction ability up to around 150F where things level off and then start to get lousy as you near 200F, but this is not the case with Parks #50. That oil is best in a range from 80F to around 108F and no more (think body temp). Below 80F and things start to slow down and above 120F and the life of the oil will suffer as well as provide spotty results.
This is yet another thing that is hard to convince people that there are ideal and less than ideal courses of action, because if the blade survives and seems to function it is hard to convince somebody not to believe their own eyes. But it is what their eyes are seeing and how it is interpreted that is issue. The reason I assembled the laboratory like facility that I have is to see and interpret things that my eyes alone can't and to determine how much my eyes were getting right. What I have found, almost every time, is that the steel working industry has developed things that work for good reasons and when you have the testing equipment to accurately measure those reasons it all sort of clicks into place for you.