Thanks for the quick reply. I had a friend propose to me that in my scenario VNAV SPD could go up to VMO-11. Apparently he read this in an LH manual. So, either LH had some modification to their VNAV SPD descent logic or the manual was not very clear and they were actually referring to a situation where the aircraft was in VNAV PTH -- not VNAV SPD -- and trying to maintain within 150' of path. The VNAV PTH scenario would be correct.
It has always been my understanding that a VNAV SPD descent (window closed) is flown at whatever speed is in the FMC target descent on VNAV 3/3 -- no additives to that speed -- because at that point VNAV SPD doesn't care about capturing the path.