Merlin negative G cutout too quick?

[IvanK]

Here is a small video. Starts with throttle at idle then to max Boost.
Then a slow descent initiation with max Boost set.
I would be interested in your opinion on the RPM needle Bounce as well as the cough which starts about 19seconds in:

http://www.youtube.com/watch?v=Py7lfQUxgRA

I figure (based on experience) that the descent entry is less than 0.2g decrement on 1G i.e by estimation G is never getting less than +0.8G ... pretty slow entry and still it coughs