Turbo air filter....

[Chamberpains]

I would imagine that the size of air line does matter. What your showing in that pic is someones rigging. I can definitely say that any kind if restrictions in the feed or supply of air affects these the response if the actuator.

If the flow of air in that picture is going from the big line to the small line, that is a restriction. I would take a trip to your local dealership with your VIN# and ask if you can get a blow up of your entire turbo actuator supply air system. Specifically anything on the truck that Cummins quickserve does not already show you. Some restrictions are supposed to be there. Like on my 9400i international, it has a psi reducer before it goes to the control module. But yours has obvious rigging. If i were you, I'd make damn sure its supposed to be set up that way. If not, fix it. It will be causing problems like slow actuator response or it may even not be traveling to it correct commanded position.