It seems clear - if you're only going to take 160 point vacations every year, don't buy 200 points... You pretty much have to "splurge" for more expensive trips every few years in your scenario.
This is what I was going to say - you're not over thinking, you're over buying. If you only plan on taking trips that use 160 points every year then that is the total number you need and you should be looking at something more along the lines of a 80/80, 90/70 etc. if you are going for two home resorts. But I have to add that you also need to look at the
point charts to see how many it takes for the accomodations you want - if your talking BLT stays every other year you probably need more points there than your second resort.
With 2 home resorts and plans for yearly trips the thought is that you will either do split stays using the current year points, or alternate resorts every other year and use two years points from that resort each trip.
For example:
BLT AKV
80 80
Use current 80 + borrow 80 from BLT for your first trip and bank current AKV.
Second year, use banked points from AKV and current year points from AKV. (and you have nothing current from resort BLT b/c you borrowed.
Third year - you now have current points for BLT and would borrow the next years points for you trip. You will also have current points from AKV that you will bank.
Fourth year - Use banked and current points from AKV. Again - you have no current points from BLT.
and so on.......
In your scenario in year two you mention banking 160 pts from AKV but that's impossible if you only own 100 points and also throws off how your looking at it. Points can only be banked once.