Odd question, maybe, but maybe fitting for this guide -- at least, depending on the answer.
For context:
The book Making Friends, Enemies, and Cakes increases the players' friends and enemies list by 100.
Both lists can be increased by way of points "up to a maximum" of 500, according to the wiki. 10 capacity increase for 50 points, with a starting list size of 10 means each list would take (500-10)÷10 or 49 uses, for 50 × 49 or 2450 points per list (4900 total). At a rounded high of 50k per point (at time of writing, the lowest in the market is 48k), this would cost a player ~$245m total, or $250k per +1 capacity.
Also according to the wiki, the Platinum PDA increases both lists by 500. $12 billion shop cost (I can't find a market or bazaar value at the moment) for a total increase of 1000 means 12m per single list's +1 capacity.
[Unless I've done some part of this math wrong... Like some others here, I'm usually fueled by coffee and Energy Drinks, but have yet to have any today.]
So my question is:
Does "up to a maximum" mean that once your lists hit 500 for any reason, they can no longer be upgraded through points? To which, wouldn't the book would see the best "cost efficiency" if used after the points upgrades are finished off, seeing as it would save a player $2.4b (200 total slots × 12m per slot) if used after the lists are 500-ed using points vs saving the player 50m (200 × $250k) if used before then)?
Or does "up to a maximum" mean that each points-upgrade can be used at any time until it's been used 49 times (per list)? To which the book definitely would truly be usable whenever, with no downside at all to speak of, or future "lost income value" if -- in the admittedly extremely niche case -- a player decided to grind their friends/enemy list size.