I'm on his discord and always catching up his streams whenever i can. I remember him saying he changed his work and art style due to irl and scarce times for the drawing. It is safe to assume the old ones take his more time to finish and they are the ones he unleash his full potential and put a lot of effort in them. When you point this out in his twitter, he is ignoring you, don't even reply or simply block you. He himself know the truth, he choose the quantity over quality but yeah you still have people saying the new ones are better than the "generic photoreal" old ones