Does "Validity shown as "enter before" refer to the exact day of expiration?

"Validity shown as "enter before" refers to the time limit of visa. The holders must use the it to enter mainland of PRC before 24:00 on the exact day of expiration"

Hi! Does it mean that I have a multiple entry business M type with "Enter before November 4th 2015" and duration of each stay 90 days, I can arrive to the immigration desk on November 4th 2015 at 9.00 am and still I can get to stay for 90 days? Or shall I arrive before November 3rd at 23.59? If the flight delayed from original arrival time, would it cause any problem? Thanks in advance!