To be fair, I would understand this argument in most industries, but, in horology, this is not an excuse. High end horology should see no corners cut and only utmost precision and attention to detail. Especially when we are looking a novelties into the several 10's of thousands of dollars. Dollars or time should not be spared in this industry, which, unfortunately appears to be the new path - IWC is clearly not alone in this.
If you're going to make a limited run of watches and market it as such, you need to number them. I can see the generic number on a novelty watch of a few hundred dollars, but, when a perpetual cal for example which costs in excess of $40,000USD cuts this corner, it is completely unacceptable IMO.. (I'm referring to ref IW502618 as an example).