just noticed the personnel includes Malcolm J Rebennack, Michael Melvoin, Milton Holland, Alfred McKibbon and Raymond M Brown. Obviously copied from the union contracts.
More economical to print larger quantities of paper to save for later - print 2500, press 1000 is/was a common practice. You can up the numbers for the "majors".
Don't know about today but 50's through 70's a union session was 4 hours and from that session you could clear 15 minutes of music. Anything over that cost more. Back then I tried to pay for 3 sessions to get 40-45 minutes for an lp. Lots of labels "fudged" the times to gain a few "free" minutes out of 2 sessions.