On 103W I can lock on 11760, 11945, 12180 but 11880 and 12080 fail to stay locked even with a 3 ft cable run out at dish with me fine tuning. I get ~80% Signal and ~35% Quality. Would a 20db gain 5db noise amp push it over enough for it to lock on?
Inline amps can improve signal strength but not signal quality. You don't have a problem with signal strength from the dish to the receiver, you proved that.