on the dot vs on time

on the dot

prep

  • Exactly; precisely, especially of a time of day. 

on time

prep

  • Punctually or according to the schedule. 

  • By installments, payments over a period of time. 

  • By a player's running out of time. 

adj

  • Punctual or according to schedule. 

How often have the words on the dot and on time occurred in a corpus of books? (source: Google Ngram Viewer )