Shelley and Lovelady were truthful in the very first statements they gave but were quickly making up ever-changing stories until the version they settled on for the Warren Commission Sham.
If Oswald reached the second-floor lunchroom about 75 seconds after the final shot, and if Truly and Baker started climbing the stairs about 45 seconds after the final shot, and if Adams and Styles started descending the stairs about 45 seconds after the final shot, how does Shelley's and Lovelady's changing their story help "The Sham Warren Commission" cover up the evil, evil CIA's or the evil, evil FBI's or the evil, evil Secret Service's, or the evil, evil [fill in the blank's] assassination of JFK?
In other words, if Oswald, Truly and Baker were inside the second-floor lunchroom's "vestibule" and therefore out of Adams' and Styles' sight while Adams and Styles were quickly transiting a corner of the second floor from one stairwell to another, how would Shelley's and Lovelady's saying they visited the railway yard / parking lot before entering the TSBD incriminate Oswald?