Exactly, that's the point minitech was making. Your statement is accurate. Saying you survive on a single millisecond of sleep each night would be clearly impossible - as is noticing single-millisecond differences in page rendering times.
You might dismiss it as pedantry, but there is a clear linguistic difference between "I notice millisecond differences" and "I notice differences of 300ms".
That's one of those places where common sense should take over literal English. When someone says 'millisecond differences', there are high chances that they mean 'milliseconds differences', and not exactly ONE millisecond difference.
You might dismiss it as pedantry, but there is a clear linguistic difference between "I notice millisecond differences" and "I notice differences of 300ms".