I hope it is the real reason, but I just feel there might has hidden reason.
PACE works fine actually. I don´t understand why you think it does not. "The others" only are looking for a pace which is more sensitive when changing running speed. But the problem is still and ever sensivity versus accuracy
And it´s also clear, that PACE is shown to fast, when distance which is measured by watch is longer than in real.
The to long distance comes from the snakeline instead of a straight trackline. But this topic is "GPS-accuracy" and accordingly "different distances GH-505/GH-625". I will write some more in the distance-topic.