Well if the AP's are on the attic, that would explain why the coverage is good on the attic:) but not on the other floors. Your signal attenuates so the more floors and walls that the signal has to goes through, the less of a signal you will have. You should have the AP's on the 1st and 2nd floors and it should maybe staggered so you can still provide enough overlap. The initial design is poor and you really can't work off of that.
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