The date is disputed. One reason I believe is that Jimmy Woode was with Ellington in 1955.
Losin makes a pretty good argument:
Although the tunes performed (especially "Jumpin' with Symphony Sid," "Ray's Idea," and "Wee Dot") might suggest an earlier date, the customary date for this set is pretty close to correct. Davis was booked as a single at the Hi-Hat Club for two consecutive weeks in February 1955, joined by Boston locals Migliori, Walcott, Woode, and Zitano. According to Down Beat, a Davis engagement advertised in Detroit for February 11-13 had to be canceled "because of a prior commitment in Boston... Davis was held over at the Hi-Hat for an extra week to share the stand with an R & B group called The Chords" (DB March 23, 1955). My guess is that the Hi-Hat engagement began in early February. (Thanks to Chris DeVito for help with this date.)
"Jumpin' with Symphony Sid," performed here at a very slow tempo, is clearly a set-closer, and the music may be from more than one night.
I'm slightly acquainted with Jimmy Woode's daughter and if I see her around I'll ask her( though I doubt that she has any knowledge of her father's whereabouts in February 1955).