We have on occasion heard the comment "APCA produces less contrast" — this is not true, though I see how some might come to that conclusion, it does not consider the totality of the new guidelines.
APCA does not produce contrast. APCA does nothing to the colors, it only predicts how a human will perceive them, and their effect on readability. And yes, if you try to compare APCA to the WCAG2 math it might appear that APCA allows lower contrast in some specific cases where one color is white or very bright, but across the entire range, APCA clearly, consistently, and correctly predicts contrast, while WCAG2 more often than not allows lower contrasts to pass that have even been shown to be unreadable, even with normal vision.
Here's an example a user brought to my attention recently: