2013 Camaro SS - down on horsepower - ignition coil trigger only has 4 volts

Hello all first post here.  
I own a domestic performance shop.  We modify, build and tune (calibrate) Chevrolet and Mopar vehicles.  

I am helping a friend with one of his customers 2013 Camaro builds.  It has a 416 ci naturally aspirated LS3, manual trans car. 
Factory ECU, wiring harness and ignition coils. 

Will having 4 volts instead of 5 volts to the ignition coil trigger affect engine performance and result in misfires?

Here are the details.
I noticed when we began running the car on the dyno that it had what felt like a slight misfire at part throttle.  You could also hear what sounded like a stutter or misfire in the exhaust. 
There were no misfire codes or codes otherwise.  
We dialed in the fueling and ignition timing and made some full power pulls. The car made 490rwhp, about 50 rwhp less than what is expected for this car with the modifications it has.  
We dug into why it might be low on power and focused on the perceived misfire. 

Using a scope we found that the ignition coil trigger was only 4 volts.  Everything I have found and read says it should be 5 volts and below 4.25 volts may cause issues.  I could not a find a specification or information in GM service manuals (Mitchell/Snap On Shop Key) that provides a definitive voltage range or a minimum allowed specification. 

My question is will or could having only 4 volts on the trigger cause a misfire or lower secondary ignition voltage output, thus resulting in lower power?
I trying to determine are we chasing a real problem or "ghost" problem with only have 4 volts on the trigger to the coils?

We testing other vehicles in the shop with same/similar GM LS variants and measured 5 volts on the trigger to the coils. 

If someone could confirm that yes, that only 4 volts on the trigger is a problem, I will provide the long list things we tried/test/swapped/measured to determine if it was a problem or not.  Then we can discuss how to resolve it.  

If someone could tell me no, 4 volts on the coil trigger is acceptable and should cause not any performance issues, we'll move on and look elsewhere for why this car is low on horsepower output.