Actually heyf00l is the one that made the mistakes, the drop rate for an 11 star item on a monster with a 35% drop rate is 1/28808 and not 1/28807.
When talking to him, heyf00l admitted that it was a mistake, albeit a minor one, especially considering his good job on the charts, because he calculated the rates "mathematically" as you put it.
So when a rate was X.1 to X.4, he would round it down, and if it was from X.5 to X.9, he would round it up.
And in the first case, rounding down was his mistake, because that particluar case was not to be handled "mathematically".
I've noticed that you're better than me as far as maths are concerned, so you will understand without a problem.
I'll take the drop rate for an 11 star item (rarity 105) from a rare monster for an example, since it is the biggest mistake he made.
His chart says the drop is 1/21, because the drop is actually 1/21.3, and therefore he rounded it down, and this is a mistake, because 21.3 is bigger than 21 which means that you need on average to kill more than 21 of that rare monster to get the rare to drop, and since you cannot have one third of a monster, the average is 1/22, that's the good answer PSO-wise.
I agree this is a very minor mistake, knowing it's 28808 instead of 28807 won't change much.
But there are two drops that I dislike seeing misquoted, and those are the 1/22 from rare monsters and the 1/28808, the reason is more personal than anything else.
When talking to him, heyf00l admitted that it was a mistake, albeit a minor one, especially considering his good job on the charts, because he calculated the rates "mathematically" as you put it.
So when a rate was X.1 to X.4, he would round it down, and if it was from X.5 to X.9, he would round it up.
And in the first case, rounding down was his mistake, because that particluar case was not to be handled "mathematically".
I've noticed that you're better than me as far as maths are concerned, so you will understand without a problem.
I'll take the drop rate for an 11 star item (rarity 105) from a rare monster for an example, since it is the biggest mistake he made.
His chart says the drop is 1/21, because the drop is actually 1/21.3, and therefore he rounded it down, and this is a mistake, because 21.3 is bigger than 21 which means that you need on average to kill more than 21 of that rare monster to get the rare to drop, and since you cannot have one third of a monster, the average is 1/22, that's the good answer PSO-wise.
I agree this is a very minor mistake, knowing it's 28808 instead of 28807 won't change much.
But there are two drops that I dislike seeing misquoted, and those are the 1/22 from rare monsters and the 1/28808, the reason is more personal than anything else.