Completely agree with the above. I was thinking of gambling on an op-up on SYD-DXB (Gold and Flex Plus) last week based on the availability figures, with Y looking full and J pretty empty with just a week to go. I ended up taking a discounted offer and glad, I did as J went out with one empty seat and Y with lots.
The numbers just can't be relied on, or my knowledge of how to obtain and interpret them isn't up to speed.