This problem has 2 levels.
First is that Testing Grounds has quite a few issues when reporting damage and the numbers you're seeing are inflated quite a bit (almost double). We will be addressing this bug and others as Testing Grounds matures over time.
Second, this does NOT eliminate the findings that S-SRMs AND SRMs are doing more damage than intended. This is not due to some top secret, behind your back weapon balancing. It has to do with splash damage, how it was first implemented and the new smaller Mechs coming out.
Here is one of the scenarios described and I've turned on the debug tools to let us see exactly what is going on in terms of hits and damage being done.
The Raven 3L has just fired 1 volley of 2 x S-SRM2 at the Commando 1B. As you can see, the amount of damage done to the Commando does not make sense. There is a total of 51.5 armor being stripped off the Commando. We've been able to reproduce this repeatedly and we're getting an average damage of 12.9 per missile. Quite a bit higher than the intended 2.5 damage per missile plus splash damage.
So what has happened to cause this? Smaller Mechs and more complex geometry than what was available when the splash damage system first went into the game. When SRM splash damage went into the game, there were a total of 4 Mechs available to the playerbase. The Jenner, Hunchback, Catapult and the Atlas. These 4 Mechs have very unique targeting silhouettes and were used to calculate the radius of splash damage per missile. Now what has happened is that the splash damage across smaller Mechs or Mechs with more complex/tighter component positioning are getting hit with more splash damage than intended.
In the image below, you can see how much overlap the damage done to the Commando has and how that it is taking significantly more splash damage than it should.
We are looking at the tuning for these hit locations/splash damage and will update as soon as possible.