Right. Like many other things about this game, it's hard to second-guess the developers' decisions on this. But it is some time around 7 PM PST. Just not at 7 PM. I'll try gathering more data.

If I have to explain why I care. Let's say I have several players at 97% condition. I have all bonuses at 10%. If I train them now, I don't get any bonus for them. If I don't train them for 3 hours, I waste 4% condition. If I know that bonuses drop before 3 hours, I will wait. If I know the bonus drop later in the day, I may as well train. It will not be every day that I will be faced with this math, but today was one of those days. I waited, until 6 PM and started training, not knowing when the drop was. If I had known it was around (before) 7 PM, I would have waited a little longer. No big deal. It just bugs me not knowing how programs work.