Getting to No Hesitation Execution

We've seen great examples of Pip executing down and leave-it with zero hesitation.  Scout has some room for improvement.  Scout's leave-its and down's are not perfect, but actually pretty darn reliable.  But that hesitation is always there.
 
I usually get a head turn with "Scout" then "leave-it" sets off a few seconds of hesitation, almost like she is processing the command and weighing her alternatives.  Usually watching me almost like she is trying to decide if I'm serious and if there might be a treat coming.  She usually does eventually leave-it, and follow through with the "let's go" or whatever, but that hesitation leaves room for her to change her mind.  I don't really know for sure I have her until that little pause is over.
 
"Scout, Down" produces the same effect.  Head turn, study me for a few seconds, examine the area around her, then slide down.  She likes to slide down in slow motion, but I think its the hesitation at the beginning that bothers me more. 
 
So where do we start?  Focus on rewarding faster responses?  Quicker follow-thru with the leash (and maybe avoiding situations where I'm not in a good position for follow through for now)?  Are we missing something more fundamental?  Watching Pip, it was like she trusted Sarah's word and did it without thinking.  Scout's wanting to double check her options and figure out why I'm asking before complying.
 
Also, is this something where we work through the response time for each command one by one?  Or is there a logical starting place that would build that "trust" piece?