Your projecting, it happens, my posts were brief and to the point and just how I would say them to your face, sorry if you perceive hostility there but it really isnt my problem to deal with.
And I didn't say you were saying anything against Thunder, just that I trust he has perceived some odd behavior that warrants further tests beyond just disproving his initial claim. If I had to take a guess I think you are getting your nose out of joint because you know your initial reply was actually a little curt and dismissive and therefore projected context onto my quick reply that simply was not there, or at least was not intended.
Anyway lets move on, we are both rude and obnoxious at times I am sure, but maybe further testing can reproduce this non amping beam situation.
Snib is correct the buff applies to both damage and healing equally, you are more than welcomed to check the script used for this ability.
There are cases where the buff will not be applied properly because of how buff stacking works, the weapon buff from the destroyer used to override beam amp, but other than glitches there isn't anything different vis a vis healing or damage.
That said if you are on a cottaro laser pointing stuff at 5KM with the damage falloff on that ship to prove anything is pointless, Aion is slightly better but still has a pretty steep damage falloff.