Chilli pollination for beginners

I recently posted about whether I needed to hand pollinate my indoor chilli plants and the advice seemed to be to use a little brush on the flowers. I have been doing this on those that have so far opened. I noticed that one of them is already forming a chilli - could someone explain is pollination per plant or per flower. Ie if one flower is forming a chilli is that plant "pollinated" or do I have to keep on with all the other flowers on the plant or they will not produce anything?
I dont like the idea of just getting one chilli per plant! I am sure I should have paid more attention in plant biol class all those years ago!

I didn't bother to hand pollinate my chillies last year and they had plenty of fruits.  Maybe it's because I leave the door open on warm days so the insects can get in.