So if I'm reading this right, Damage Control (with Intellect/Mechanics) can only ever repair one point of HT no matter how may successes are rolled. OTOH, Manual Repairs (with Brawn/Athletics) repairs one point of HT plus one additional point per two additional successes. Both are subject to the same once per encounter limit, and while Manual Repairs is more difficult, it can have a higher return. Why can't Damage Control repair more HT with additional successes?
Assuming that Manual Repairs are supposed to be somehow superior, why don't Technician (Mechanic) characters get Athletics as a career skill? [Just kidding!]