All times on the documents are rounded times, 3:00 pm, 1:00 or 1:15 pm and 3:30 pm.
Nothing precise can be read into these times they are all rounded roughly to the nearest 15 mins.
My guess is that Tippett arrived between 1 and 1:15, and initially they went with 1:00 but rounded it to 1:15 instead.