Hi mm43;
Thanks for sharing my curiosity. I think your translation is perfect and, yes, I believe it means what you say (i.e. the 'freeze & latch' corresponds to the CAS & Mach at 02:10:04,5). The "short-term Mach fluctuations prior to the defining one" must have been pretty large, and must have come from a different source than the recorded CAS & Mach. Then there is the value itself, which doesn't correspond with IR #2:
1.12.3.5.5 Examination of the Rudder Travel Limiter Unit (RTLU)
The RTLU was found in its place in the fin and disassembled. An examination was performed at the manufacturer’s and showed that it would allow travel of the rudder measured as 7.9° +/- 0.1°. As an example, at FL350, this travel is obtained for Mach 0.8 +/- 0.004, corresponding to a CAS of 272 +/- 2 kt.
Note: the maximum travel of the rudder is calculated in relation to the airplane configuration, its speed and its Mach number. This travel can be commanded between 4 degrees and 35 degrees.