Think about it like any other product, theres different degrees of quality you would expect at different price points. I dont know how much youre paying for a crown design, but I can share with you what my expectations would be.
Accurate margin selection at any pricepoint should be assumed or you need to find a new group to outsource to
For $4 or less, I would expect an occlusal plane that matches the adjacent units, cusp heigts that match the adjacent units, automatic functions applied to form contacts and a distance to opposing unit to some predetermined parameter. I wouldnt expect significant recontouring implemented post those automatic functions, probably only a few base anatomys utilized that are easy and quick to work with, in short a bare minimum but par crown.
For $5 to 10, I would expect a little more. Contours defined to be more harmonious with existing teeth, manual modifications to retain form after contact points are defined, excursive movements and hygenics to be taken into account. At the higher end of this spectrum I would also expect the designer to be able to communicate any potential problems that client may face when working on the case.
For $11 to 15, I expect absolute consistency to the point in which the cases no longer need any form of quality control prior to being milled unless there are special circumstances. If youre paying this and finding more than an occasional problem with the design, then you shouldnt be paying this
For $16+, unless there is some special circumstance, you are paying too much
