So, we have two reports ( from the DPD and the funeral home) which show the time of death altered? "corrected" from 1:00 "ish" to 1:15. (We should be thankful, I guess, that Whiteout and Liquid Paper had not yet penetrated the mass market?)
Since Oswald's landlady saw him at 1:03 ish standing on a street corner, at a bus stop, the OP's 1:15 time of shooting is doubtful, to say the least.