The reality is, at least in the Eastern US, that you probably don't successfully receive the signal often enough to ever get the DST bit. When I lived in Chicago, I used WWVB clocks and they worked fine, when I moved to New York, I never got them to sync. I also have a bunch of chips for receiving the signal and they have never worked. You have to use the new phase modulated signal, and nobody sells chips for receiving these. (Naturally the older AM receivers are a cheap single-chip solution. So would a receiver for the phase-modulated data, but nobody feels like making one, so you are stuck.)
The reality is, at least in the Eastern US, that you probably don't successfully receive the signal often enough to ever get the DST bit. When I lived in Chicago, I used WWVB clocks and they worked fine, when I moved to New York, I never got them to sync. I also have a bunch of chips for receiving the signal and they have never worked. You have to use the new phase modulated signal, and nobody sells chips for receiving these. (Naturally the older AM receivers are a cheap single-chip solution. So would a receiver for the phase-modulated data, but nobody feels like making one, so you are stuck.)