ED used only for one episode?

[meidei]

Something that came suddenly in my mind, wasn't there an ED song in the anime that was used for only on episode and then they reverted back to the previous one. Somewhere in the #500s. Is my memory correct? I've been watching the episodes after ~500 really far apart each other but I am under the impression that there was an one-episode only ED somewhere. Since it wasn't a special episode I thought it was a copyright issue.
Anyone with stronger memory here?

[kkslider5552000]

even DCTP's bonus B'z one lasted for more than one episode so...?

[tangytangerine]

Unless you're talking about the Hikari ED(ED 34) w/ a B'z song DCTP used for episodes with an ED that had a phone number for a contest, there hasn't been one.  Even then, that was used for 7-8 episodes.

[meidei]

I think I found out what ED confused me. From episode 567 and thereafter the ED was Pray by B'z, which replaced Hello mister my yesterday by 100% Free. It lasted for 4 episodes, and then it's back to Hello mister my yesterday for all the episodes after 570 (until 587 at least, that's the last episode I watched).
571's ED had indeed a phone number but I still don't get it. DCTP changed all following EDs to 100% Free's song to replace the phone number ending or it's the studio's doing?

[Jd-]

The rundown:

1) Call-in endings began airing.
2) We replaced them with a custom-made ending whenever possible for that run. The song used was PRAY by B'z.
3) New ED started.
4) More call-ins started, so we made yet another custom ED. The song used then was Kirei na Namida, also by B'z.