Personally, I think its more of a styling choice. In the end many very expensive dress watches from Patek, Lange, VC, etc that use pushers that are flush with the case, so I don't know that its a real cost issue, as they have no need to cut corners, particularly if one considers their pricing. Spot on Frills! Even at a good price for the Double Red Sea-Dweller, no box and papers would be a deal breaker for me. I just could not do it. If I am spending that amount of money for one, then I'd probably be willing to put in more money and buy one that's mint with B&P. I think one can own several perpetual calendars and/or perpetual calendar chronographs, and if there is a enough variety in terms of design, case metal, and movement one can enjoy them without feeling they are redundant. However, something as basic as a Calatrava, is going to be unnecessary, or redundant when the 3940, 5040, a 3970s, do everything that a Calatrava does and more. I would not feel regret over using the Calatravas to take some of the edge off of a more complicated piece. To me that makes sense. The 5205 is an interesting design, I like the pierced lugs, but overall I don't love it. If going for something with windows for date, date, etc...I prefer some of the more classic designs one might see using windows for day and date on vintage PP perpetual calendars from say the 1940s and 1950s. Also, as you have pointed out the price difference between some of the annual calendars and mint condition with box & papers real perpetuals isn't that far off. I would DEFINITELY, spend the extra and get a real perpetual calendar. Sure its a lot of money, but as my Mom used to say, "Its never the last hundred, its the first thousand." Meaning once you are that far into it, don't hold back just because its a bit more. Granted in the $2K-5K isn't a few hundred, but in the grand scheme of things when you are talking roughly $40+K its really not that much. Beautiful JLC!