They can't pulse people through in groups because the crowds have become too large. They used to do it that way. Now the cattle chute is the only practical way of doing it.
There's 7 houses. Only 1 has chainsaws. So I'm thinking you DID go through the same one. If they all seemed the same to you, I don't know what to tell you. Personally, if I were blindfolded and guided into a house, then had the blindfold taken off, I would immediately be able to tell which house I'm in. And I've only gone through each one once so far.