It is perhaps worth noting that the 25,000 bit flips/out of 470,000 crashes (in a week) are probably not coming from all Firefox users. It would be useful to know how many of those crashes (and bit flips) are happening on the same machine. And whether the crashes/bit flips continue on the same machine continue from week to week.

I can certainly imagine that a very small fraction of Firefox users are generating these results, so that bit flips are not a problem generally.