The filter is basically:
current value + ((|new value - current value|)*constant)
I know this is an ancient thread, but this formula HAS to be wrong: Because of the absolute value, the parenthesis will always be positive so you would always lean out even if requesting a rich mixture.
ex: 1 + (| 0.8 - 1 |) *1
1 + (| -0.2 |) *1
1 + (0.2) *1
=1.2
I assume it is correct if we remove the absolute value as that would give the expected result.