honest answer if you can tell me

First of all, tier means absolutely nothing to the bid matching process, okay? So, no, it is not all your choice but how the order of preference you put on your card matches the houses' ranked bid lists. What happened was that you weren't dropped by your number 1; you just weren't ranked high enough on their bid list to match with them before they reached quota. A house's first choices are matched with the pnm's first choices until that house reaches quota, then they are done. At that point, the algorithm would try to match you with your number 2 choice, and if you match with them before they reach quota you get a bid there. If you don't match with them either you still get a bid as a Quota Addition, but the bid could be to either house depending on a lot of considerations in the algorithm. You are guaranteed a bid if you rank both houses (or just the one if that's all you have at pref) but not necessarily a bid to your first choice. If you don't put each of your pref houses on your card (suiciding) and your only house reaches quota before they get to you, they you can't be a quota addition and you don't get a bid at all.