Subjectively, that difference is not as great as the first, although objectively it may be much greater. I'm too tired to type in the whole silly thing. The risk of indicating an incorrect floor or not indicating the current floor is much harder to eliminate. Here are some further details. This problem is as old as the hills.
Statisticians routinely throw out the absurd values before computing the mean.
We also have a problem of nonunique clock readings during the hour at 2AM when Daylight Savings Time ends. A good time to be asleep. It it unfortunate that there is no way to get the current year out of the WWVB clock. Sorry about the problem. Your errant clock reminds me of something that happened at Stanford in the mid-sixties.