Hello,
Impulse is supposed to be used with Automap for DAW interaction, pure MIDI mode was thought to control Hardware. And so the documentation is not so detailed/clear how to use MIDI mode to adopt controls for not Automap based DAW/plug-in control. If you know the link to (un)official Impulse MIDI (internal!) protocol specification (f.e. exists for Launchkey), I can read it and give you more details.
There are 2 used general way to control parameters with encoders without jumping/catching. Which are available for Impulse is not clear from the user guide (may be both, but probably at least one):
1) configure encoders to send changes instead of "absolute" value, so they send "+n" when turned right and "-n" when turned left (where n is 1 or more, when you turn fast). That it is not required to send current value back. Sure, Impulse display can not show correct current value, but you can modify parameters without jumping. In "ACT MIDI" plug-in, Ctrl+Click on corresponding control to open advanced configuration dialog where you can set that mode. But you need it to set it on Impulse first.
2) encoders get "feedback" from the DAW which tell them current value. "ACT MIDI" does not support that. Automap obviously does. AZ Controller also (since there is no general rule how to do this right, "Startup preset" does not include such "feedback" out of the box. In practice, for Novation, I guess one "Action" per encoder should be added in each corresponding Feedback list, "MIDI <Use Ctrl> <Value>")