As limited editions generally are 500 or sometimes 300 (Kernow's recent Hornby ones for example) then it must be lower
'The question is why are models discounted in the first place ? Is it because the manufacturer has produced too many, and/or priced them higher than the market will bear, so the shopkeeper has to reduce the price to shift the stock ?' - same with any product really, it gives competitive advantage to retailers doing it when its in demand or allows them to release funds when not selling or when they need cashflow