"Last" is when -
A) it's been a busy night and Tencho wants to give the girls a break,
B) Tencho figures they've made enough money for the evening (same day that Hell is selling snow cones),
C) there haven't been enough customers in the past couple hours to bother staying open any later,
D) the regular customers have figured out that all the good looking girls have taken the day off and business has dropped off,
E) a Gaijin shows up and they don't have any staff who will work with him,
F) it's been pouring rain for hours and no customers are horny enough to brave the storm for a BJ
G) Tencho is in a bad mood and just says "Fuck it" for the day,
(Any other ideas?)