Nice theory wowzz, but from what has been said it seems that the early morning check in availability has been reduced to 2 hours before departure of the first flight. I would be very surprised if this was not part of a renegotiation between Aviance and Jet2 aimed at cutting the bill for services that Jet2 receive. To then expect that Aviance open check in early because there is a queue is unreasonable, as I doubt that Mr Meeson would be at all thrilled to receive an extra charge for that.
Airlines only have a finite number of tools in their cost reduction box, and minimising the fee they pay for ground handling is one of them. Unfortunately the less you pay the less service you get, whether it is reduced opening hours for check in, or a reduction in the quality of service they receive as the handling agent is forced to reduce the wages offered to their staff.