Tuffy - I don't think getting to the PBO has anything to do with the monthly contests (tho I know they had a few monthly contests this past year ... I don't know if its something they do often).
The best way to 'learn' more about the PBO is to scroll up to the top of this site - it should say 'bake off contest' -- click on - and you'll have a LOT of options to look at and read about. It gives a LOT of good information and should answer at least a few of your questions.
Yes, you're right - that info on the next PBO - will come out sometime after the upcoming contest in April of this year. But, usually not right away. The PBO is usually held every 2 years ... so there is lots of time.
In the past PBO has never really said how many entries they receive .. but for many many years I've heard and read in newspaper accounts, etc...'tens of thousands'. My guess is that there are many many more than that. Of course, many are cancelled out immediately .. for things like not following the rules -- simple mistakes .. but easy to do. I have read that in PBO (and other cook off and contests) the other recipes are read -- and (I am guessing) rated to a degree .. and then a certain # are again checked .. and then those are tested .... and out of those they chose the 100.
PBO has always been very fair -- supposedly the names, addresses, etc. of who sends in the recipes are removed (code added so they can check back I am sure!) So the staff doesn't really find out who will be their finalists until they're chosen.
It is a thrill to get the call telling you that you are a potential finalist. They will ask you some questions right away (to make sure you followed the rules and that you are eligible) and then there will be lots of forms you will fill out (now done on line) and it still takes some time after that until you are officially informed that you are a finalist.
If you get that far - you get the expense paid trip to compete in the PBO .. and a chance to meet so many people, have some fun (PBO differs depending on where it is held and what activities they have planned for the finalists). It is a busy time - but brings wonderful memories. You can bring a guest, if you wish, tho the guest can share your room for free - he/she will have to pay to go to the activities, meals, etc. etc. Prices go up all the time. You will (or you should) meet lots of new friends and have wonderful memories .. and, if lucky, bring home a prize.
I (and some of my family and friends) have wonderful memories of past PBO's ... I'm no longer eligible (as I've been 3 times) but I was also able to attend a couple of PBO's as a guest before I went my 3rd time. Each was a lot of fun and enjoyable. And I (and they) have lots of fond memories.
So take your time ... but do check up on the bake off - way up above .. it is fun to read about some of the old ones .. and also to look at many of the recipes (and make some) ... and good luck to you. Sit back and enjoy what's coming up .... there is no rush.