Plus the close-ups are not happening at the same time as the main shots. In both Sendai and Jintsuu's cases, it's a before-and-after pair of pictures -- the close up of them in the middle of removing their underwear is the "before" pic and the main shot of them holding their freshly-removed panties is the "after" pic.
I'd second the motion for a new pool pending both that someone can come up with a clever title and MTU does a pic of a light cruiser other than Naka.
Also, the destroyer upskirts segment of this series hasn't been finished yet because the artist has yet to draw Shimakaze
Panties that aren't hidden don't have the pride of panties. It's the same reason you giftwrap a Christmas present before giving it to a friend or loved one -- if it ain't wrapped (preferably with a cute little bow) then it ain't a Christmas present, even if you give it to them on 25 December.
Sure, we already know what she's wearing under her "skirt," but unless we can get to see the part that ISN'T always showing then it doesn't count.
what if she's wearing knee-length bloomers under her skirt?