[Avodah] Selichos - Especially before Midnight

[kennethgmiller at juno.com]

R' Richard Wolpoe wrote:
> Rav Gelley has said many times that Breu'ers does not say
> X or Y because their minhag pre-dates the inclusion of X
> or Y into the Davening - IOW the minhag is older than Rema!

I'd like to know how this works. At what point did the kehilah say "Today is the cutoff. Things we've added until now are okay, but no more new stuff."

I ask this because it seems clear to me that they DO say some things which were added after Chasimas HaGemara. Like Slichos.

Akiva Miller