I mean u cant really rely on carbink/diancie number of balls thrown rate for there is a resp that only spawns Carbink, unless you're 100% certain this person hasnt gone there. Also, 100 and something respawns is far from a reliable sample to jump into any conclusions when we're talking of a 5% rate. Trust me when I say I'm the last person you need to teach anything about catching odds on this game.
And I think you misinterpreted my last sentence. As I pointed, I know crystal clear the number of balls I've thrown so far doesnt increase a bit of my chance of catching, at least when it comes to pokes without extra, which is the case. Thats sunk cost. I said that cause as you said I had every reason to support your idea. It would definetly make things easier to me as well. But I dont think it's fair to those who already caught, and thats why I dont support it. Not because I've already thrown 200 balls.
Last but not least: This game does require u to grind really hard to achieve great things. I'm likely the closest player to get Master Ball, what is supposed to be the ultimate goal. The only thing between me and Master Ball now is 50th zygarde cell, for which I need to finish all Akala's tasks from npc Ellen. I suggest u take a look Task window from players profile (its displays each pokemon once, but you have to make each of her tasks 3x). Not to mention other stuff I had to do, like throwing 22k ball to catch an Aerodactyl. To accomplish this, I've given up many other goals I'd like to try.. dueling for example, or intensively going after shinies. Its a matter of setting your priorities and go for it. If I were you, I wouldnt bother at all trying to kill 700 diancies, its not worth for a single rare card. Just like I believe its not worth to evolve 10 snorunts into Glalie just to get a rare card. And this is not me trying to tell you what to and not to do, this is solely my opinion on this matter. Some achievments are simply not worth it