Definitely more passengers than shown ... I believe, when a station is "overloaded" the last line of passengers fades out, then as passengers depart, the queue updates, but sometimes gaps start to appear in the display. I've seen three blank rows of passengers.
This problem comes up often for me on Osaka, and might be a useful test case, though I haven't noticed passengers travelling outside in Osaka.
I set up Osaka with a minimal plan -- a three station tight triangle/dot/square loop with a couple of lines connecting all the uniques to the square. And I make the triangle an interchange as soon as possible, and feed it using relief lines just with the fast trains. Sometimes 3 full trains arrive at the same time, along with a locomotive to shuttle square passengers out of the triangle. I've noticed with this method, that the station takes a long time to get a count down timer, maybe because so many passengers are coming and going at once, or maybe because a counter is screwed up???
Regardless my efforts... I haven't been able to get past my top score for quite some time :(((
some screenshots ... the square station w/countdown timer... with mixed up queue
the square station again, after three trains dispatched... still mixed up queue