Action Level adjust not accurate

Hey All,

I’ve programmed an action to adjust the send level of my singer in the Wedges and Fills depending on what he does with the mic. The actions are Input -4.0 db in those mixes and input +4.0db in those mixes. Problem is that the actions performed are off by some fraction of a db, so over the course of a show, I end up sending more and more to the mixes.

See video to clarify.

Have tried this at 3.0 and 4.0 db values, and I get the same problem.