Errata for NIST SP 800-63
When NIST put together the table A.1, they accidentally used a 96 character alphabet for that last column, not a 94 character one.  One way to see this is looking at the bottom most entry; they list that $log_2(b^{40}) \approx 263.4$, where $b$ is the alphabet size they used.  If we solve for $b$, we get $b \approx 96.002...$.