Just to chime in, hammer shot is a filler in your rotation. It's primary purpose for a combat medic is to build 30 charges so you can activate your supercharged skill. I like to use hammer shot on the main tank's target at the beginning of a fight and then switch to use it to top off teammates later in the fight.
Similar to scoundrel's diagnostic scan, the healing component of hammer shot is just a little added bonus.
Also, at level 40ish, commando has enough tools to feel like a solid healer.