I don't know whether Bird's playing on this recording "is at a level notably higher than any Parker had reached before" - I'd have to do a lot more listening before I could make that statement. In the end, it doesn't matter. Bird sounds at ease, seemingly in a good frame of mind, and he plays beautifully here.
Thanks to Dan for starting this thread, and to Larry for his comments. You guys got me to listen to this music and to enjoy and appreciate it once again.