Which still won't be enough when you're near the bottom. Sometimes there are so few trips left that PBS can't find a way to them on your line with the default settings. I would suggest at least

Waive Day Off, Min Days Between Work Blocks, 1
Award Work

Or the full Hail Mary bid group as the last one. Twice this year I've had Award Work as my second to last BG, didn't get it, but used the above as my last bid group, and got it. That waive is not too painful. Better than reserve.