E78 Knock Learn Down

Knock Learn Down is the rate the Knock Learn Factor is decremented when no knock is detected.

My questions are

1) Is the learn factor decremented based on total reported KR, or by the intensity of each individual knock event?

Attachment 135957

So given the table above, if 2 knock events occurred in quick succession, one with 6deg intensity and the other 3deg,
would the Knock Learn factor rate decrease by 0.0030 for the the 6deg event, and 0.0011 for the 3deg event?
Or would it decrease by 0.0035 (10deg total KR) until the Learn Factor returns to 0?

2) If the multiplier was set to 0, would that mean the Knock Learn Factor would never be decremented ?

Thanks!