Transmission overflow

Recently, the rubber hose that runs from the top of my transmission to the metal breather hose had dry rotted, and was causing a massive fluid leak. After replacing the hose, I had accidentally overfilled my transmission with fluid. The extra fluid came out of the breather when the car was shut off. After 2 days of this, I had the excess fluid sucked out of my transmission, and the level was adjusted to where it should be. After driving the car around for a month, I just checked the fluid levels today, and found that my transmission was low on fluid. I looked below the breather to see if fluid was there, and there was a puddle. If anybody has any idea as to why my car is doing this yet, blowing out fluid when the level is ok, please let me know. Thanks.