Horn Replacements

In late July/early August, METX167 came out from its 3-year inspection with one of the worst horns I haveheard to date. Only the 3 and 5 bells function all the time; the 1 and 2 come in and out and if they aren't sounding they just squeal to all heck. My first question is does M19A send the horns off engines to the Rocket House? I've heard some of the horn replacements that have been going on for about a year on MILW; I'm only concerned about 2 horns - 100's and 107's...Every horn that UP has replaced on the 127-180 group sounds like it hasn't been touched, just swopped...I don't know what M19A does with horns; I'm just noticing that the horns aren't sounding any better then when they went in; in some cases they sound worse. Listen to this example of 155:
http://www.ctrgroup.net/folder01_004.mp3

Uhh, the only thing that happend to 100 is it changed from new to old casting.

Well,

I should say that the horn has squealed in the presence of my recording equipment, but for the most part all the bells work and sound really great.

Eh, the occasional squeal isn't a bad thing.