That's why you always put up the influence trade before asking for something - the game runs every integer trade value through whatever algorythm is used to determine whether AI will accept the trade.
It does this for money, too. Which is very annoying when you're running a treasury of ~5M.
That means the AI is more likely to accept the trade at a lower numerical value, and even if it doesn't accept it doesn't take several minutes to determine that it won't.
Except if you have it down to 3 planets and you're trying to buy them. Then it takes 45-60 seconds and eats up 100% of one core to do so.
If there's one thing I want fixed in GC2, it's this. I can almost find the value faster than the algorithm can, when we're dealing with numbers that high, and I'm only human.
And it's sad that I've already reported the bug that it tries every integer value. 