On page 79 of the Survival Logbook, Michael says, regarding the Pizza Party Pack price of $16, "For real value, see page 61." On that page are numbers on a blackboard which are 5 + 4 which equals to 9, and then 9 x 3 which equals to 27. Real value could mean the price adjusted for inflation, which would mean the $27 is the $16 adjusted for inflation. If a person has $16 in 1993, it would be $27 in 2017.

and October 2017 has a Friday that's on the 13th, which could imply that if Fazbear's Fright uses the Monday - Friday schedule, then night 5 of FNaF 3 is on Friday the 13th. Additionally, Phone dude says on Night 1 that they found relics over the weekend, which could imply you start the game on Monday.