I can't understand his attitude. Autobiographies and interviews always must be taken with some grain of salt, memories can fail. I experienced that while researching Pony Poindexter's discography while consulting his memoirs. Some of the dates he remembers are unplausible, some are exact to the day and pass the test.
Oh, and discographers can be mistakne, too, unless they get acces to a label's vaults, which rarely is the case, and even then ..... all of the dates for Cal Tjader's live recordings for Verve are one week off. There are reliable concert reviews that tell the correct dates. You always have to double check.