It truly is a horrible car park. No idea how many bays, must be close to a thousand. And it has one main entrance/exit. There's an extra entrance (the one in article) only if you are coming from Walter road heading East and one extra exit only if you are going Up Wellington heading North. None of it makes much sense.
I suspect the problem has arisen from the success of the place. Between the decent food options and Spud Shed, the place has become more popular than the planners expected.