Sounds like good practice to me. Excellent news that stuff is in production!
The a600 micro-crack issue sounds interesting, and makes sense. I would have thought people need to be made aware of this up front and offered the service at a fixed price in the event that the accelerator does not work, however I assume that's what you're thinking of by insisting on the reseller being able to fix it
Do you have a budget estimate for the accelerators themselves? I don't think I've seen a price on the 600 one yet.