It would be more like trading a Shetland Pony in for a Holstein Warmblood??? Using a horse analogy (grew up with horses and family breeds Warmbloods and are involved in Dressage, I prefer First Cross Quarter Horses but ride Litre bikes and MTB - safer 
).
Given the backers have been the financial foundation of the 5K / 8K project and also Guinea Pigs for software development, some incentive to upgrade would be appreciated. If one is also having to RMA a poor quality product, would it not be fair to offer for a price differential for another model if the customer is prepared to pay it???
Anyway think of it as a rewards program and also Backers can be very good form of marketing.