Timing of the Boston tea party

I just watched this again and I'm curious. Johnny rides his horse and tells everyone that they owe 6 shillings. meaning meeting at 6pm. According to uncle Nat, they were talking for over and hour and must be thirsty, Meaning it's now after 7pm. They go to Old South and have a meeting. After Samuel Adams gives the code phrase, They go to the docks. This is where I'm puzzled. The town crier calls out "7 o'clock on a fine night and all's well". How could it be 7 o'clock when chronologically it should be well past that.