If the design is correct you have two concave surfaces , one flat one and one convex one So from a testing stand point it is easier to test then the other designs. The two concave surfaces can be tested directly via the Foucault test. The flat surface tested by interference against a Master flat surface. The convex would require a concave test plate and tested by interference. The convex surface would have the highest level of error being tested with a test plate, the other three surfaces could tested with a high degree of confidence of their surface quality. So the elements could quickly be tested and one would have a higher degree of confidence that when assembled into an objective it would perform well without any farther tests. Since time is money I believe this may have been the reason why this design was chosen over others.
I love this explanation. Just love it.
Goto hardware is premium relative to other retail telescopes at the time.
As a manufacturer, what are your choices?
1. Commit to the luxury market and not concede on price - smaller volume/greater margins.
2. Concede on price, and embrace thinner margins relative to your lower cost competitors.
3. Find cost savings elsewhere and work a broader upper-to-luxury segment in defense of your margins.
If Dave is right, and the economics of testing afforded them some cost savings with their particular optical choice, then they could surrender some on price (thereby allowing them to compete better with retail RAO despite greater hardware costs), but still lay claim to the luxury retail market.
It would be so interesting to see marketing materials from back in the day - to show how Goto sold its wares relative to other retail manufacturers.