I want to preface this by saying I believe this to be a bug, rather than working as intended.
Currently Adaptors give a "5%" boost, though we all know this to not be true and in many cases can reach above 15%. This is most noticeable in five card decks, but is also present in four card decks and even two card decks. The reason for this is that the boost is being applied to the cards in groups rather than individually and this causes certain cards to receive the adaptor boost multiple times, up to five times in total.
For those who just want the equation, here is the simplified equation:
(AdaptorBoost)((5 * ATK 1) + (4 * ATK 2) + (3 * ATK 3) + (2 * ATK 4) + ATK 5)
ATK 1-5 are based on the order of your cards as seen from top to bottom when editing your deck.
AdaptorBoost is the boost provided by your adaptor. (Currently is 0.05)
It is not uncommon for the total to be off by a few points due to rounding.
The formula in theory should also be the same for defense.
As I haven't done testing of this on decks containing multiple Alignment cards, I am not sure how this would work on them. The equation should not be drastically different and just need the number modified to fit the deck composition, or it may very well be the same if your Alliance owns all adaptors.
Why this happens is the game is actually applying the boost in groups. Rather than just taking the total ATK of your whole deck and multiplying it by your booster, it takes the first card of your deck and multiplies it by your booster. Then takes the first two cards of your deck and multiplies it by your booster and adds that to the previous boost and continues to add a single card at a time and adding that boost to the previous boost total. The full equation would be as follows:
(ATK 1 * AdaptorBoost) + ((ATK 1 + ATK 2) * AdaptorBoost) + ((ATK 1 + ATK 2 + ATK 3) * AdaptorBoost) + ((ATK 1 + ATK 2 + ATK 3 + ATK 4) * AdaptorBoost) + ((ATK 1 + ATK 2 + ATK 3 + ATK 4 + ATK 5) * AdaptorBoost)
This means you can increase the Alliance Adaptor boost by putting your cards with the highest attack at the top.