Since deckbuilder has the convenient feature to track, which cards are already part of a deck, I started inputting my commander precons (in private mode), so I activated "in collection", set the filter to Brother`s War Commander and started doing the Urza deck.
However, after adding
Swiftfoot Boots, it suddenly said -1/1 card left, so I started checking that I indeed had multiple version from Standard Brothers War, too, and that indeed, the one card I already added to another commander deck was set to a standard Brothers War card.
After pondering a bit I realized, that deckstats counts
the total number of cards I used in all active decks (2) regardless of filter settings against
the total number of available cards due to filter setting (1)
Maybe you could activate the filter for the first number, too?
2nd: I later checked, I can see in my normal collection, which card versions I own, but deckbuilder only shows me the number of cards according to the filter. So if I want to sort my physical cards according to set and then want to search for the cards, I used in deckbuilder, I will have trouble finding a free physical card, because I have a hard time determining which set version is "free". (That may be easy for some of the rarer cards, but imagine checking 20+ decks for all in use versions of
Path of Ancestry...). It would be great to have an overview, which version of a card is occupied instead of just an overall total.