I think Go North East have this allocation because they see the passenger numbers justify it. As has been said by more than one person before - Go North East know how many passengers use their services.
Granted, having standees at peak times (taking Lee's word for it - never experienced it myself) is not the best of things, but surely it's not the worst of things either; all buses have dedicated room for standees, so they should be catered for regardless of whether or not they can get a seat. The only real problem, in my opinion, is when passengers are refused travel due to so many passengers.
Go North East: 2014/15 Financial Year Order Predictions
bazmaba