What goes around comes around? Jay Leno’s ratings for The Tonight Show are still lower than Conan O’Brien’s ratings were before he left NBC, according to figures published by Neilsen on Thursday. Leno’s ratings for the week of October 25-29 averaged a 0.9 rating with adults 18-49, while Conan averaged a 1.0 with the same demographic this week a year ago. Another bad sign for Leno: For the first time since his return to The Tonight Show, his ratings were bested by David Letterman’s Late Show on CBS, which averaged a 1.0 rating with adults 18-49 last week. This shift in late-night power is timely, as Conan’s new show on TBS begins Monday.