PC version has a load remover that detects internally when the game is loading. Console (obviously) can't have anything like this to the same degree of accuracy, and attempts to have a video based load remover didn't really go anywhere, so it's timed with the In-Game Timer, which is generally considered inferior.
Because they use different timing methods, the two versions are not really comparable at all, so they can't share a leaderboard. I believe the boards are completely separate as opposed to being split into subcategories due to site limitations.
Exactly what Riko said. And to clarify, the site limitation is timing order priority. Say we wanted In Game Time (IGT), Time Without Loads (TWL), and Real Time Attack (RTA) all on the same board. We could leave TWL blank for Console submissions, subcategorize PC vs Console, and easily have each board cohabit the same page, but if we have all 3 timing methods enabled and we choose TWL as the main sorting method, the site assumes that we want RTA as second and IGT as last, which would mess up the Console boards. We can not choose the secondary timing method.
