I know you're kidding, but check this out:

1 nanosecond is 1/1000000000 of a second, or 1.0 x 10^-9.

2 nanoseconds per day, cumulative error, 2.0E-9 * 365, is 7.3E-7.

Still doesn't sound like much? Light moves at 186,282 miles per second. In 7.37 x 10^-7 seconds, light moves 0.136 miles. Or 718 feet. Going from 11 to 8 nanoseconds improves positional accuracy a noticable amount.