bear, FFS, the transcript isn't parsed to fractions of a second, and he may have noted 8 grand in passing or nine grand in passing and approaching ten grand ... your division presumes a precision in your chosen "data points" that isn't in keeping with the accuracy you wish to assign to your RoD estimate.
If you make the denominator 0.75 seconds or 1.25 seconds to accomodate time to speak and delay between reading and speaking, what numbers do you arrive at? Keep moving your decimal fractions about until you get the numbers you are looking for?
Come on, bear, you know better than that!
Given that the FDR apparently produced some data points and readings around 10,000-11,000 fpm down (closer to the latter), such data is quite enough vertical velocity (or the vector along the negative z axis ) to evoke a grimace on anyone's face who is familiar with flying. There is no need to employ hyperbole and inaccuracy in attempt to craft further drama. There is drama aplenty without resorting to such.