Is it really that odd ? 130 isn't many at all, and the on-sale date was published before today so easy to imagine there were more than that logged on and waiting at 9am given the known limits on parking availability. We've had instances of several hundred away tickets selling out in minutes when a new tier opens.
I think it's just out of keeping with previous parking sales which I think normally took several hours to sell out. Maybe suddenly everyone was more on the ball than normal and, as you say, if you happened to look yesterday then they did at least put that they would be on sale today which is more than they can normally be bothered to do.
So annoying if you were one of those who missed out but I'd be willing to bet more will appear at some point but it's the same old case of logging on and checking every now again and hope you're lucky. But they don't half make it hard work to be a fan at the moment!