Da Vinci 1.0 stated maximum build size not possible

Even if the build size is specified as 200 you would never actually go out to 200. The temp around the edge of the bed will be lower than the middle and average print of area of about 150mm. You could maybe push 180mm but even then it is iffy. Are they false advertising? Could be, depends on how they and others define build area. This is the case with most printers. You never want to use the full size of the bed as it can lead to adhesion and lifting issues along the edge of your print. At least this has always been my findings. Could be just bad bed design as well.

Also only one post is needed. So you might want to go back and delete the extra.

Well not to defend them but in theory you could reach that volume of your objects base was smaller then got larger as the layers went up. So yes 200 by 200 would be achievable as long as the base of the object fit between the glass hold downs.

Of course your going to find many more problems down the road with your purchase choice and XYZ's <cough> warranty. There are many mods you will probably want to do as you will go and see some of the short comings. I had one and liked it but it needs some work to get it printing really well.