During episode 1x02 - The Fastest Man Alive Barry and Joe have the following conversation in the lobby of the CCPD:
Joe: I always had a very simple set of beliefs. Gravity makes things fall, water makes things wet, and up until a few weeks ago I believed the fastest man could run a mile in 4 minutes, not 4 seconds ...
Barry: I can do it in 3. [of Joe's annoyed look] Not relevant.
Unfortunately for our forensic "scientist", Mister B. Allen, 3 seconds to a mile is a bit faster than 1.5 Mach (even Joe's guess is only slightly slower then 1.2 Mach).
Yet in 1x06 - The Flash Is Born everybody makes a huge fuss about Barry never having run as fast as the speed of sound before and actually needing a few miles of lead-in to finally reach that velocity.
Is this just an instance of Writers Cannot Do Math [WARNING TVTropes Link !!!] or did I miss something?