Don't forget also that in addition to the complexity of assembling the example discussed with 8 different colors (or indeed anything more than 4 colors repeated) you also have to make clay, slugs and then spots in all those different colors.
The spot levels are all calculated based on a combination of time taken to make those components, assemble them, and differing wastage, based on physically observing and timing those processes. That is why some that look simpler visually may be in higher levels than some that look more complex - there could actually be less stages involved. Rather than say we can't do something because it is more trouble than it is worth we took the view that it was better to just try and accurately price everything accordingly. In reality, profit on a Level 12 chip will be no more than on a plain chip. And as mentioned in caveats on other occasions, we would not always agree to do a high quantity of a very complex pattern regardless of price as it could be too much strain on employees (seriously), unless the customer is happy to wait 6 months.