Game logic question concerning Yahtzee rules

I need someone that really knows Yahtzee well.

I've nearly completed my Yahtzee clone. What I have left is to keep track of Extra Yahtzee Bonuses. These are Yahtzees rolled after an initial Yahtzee has already been scored in the Yahtzee category. I have some questions about this.

1] Must the player use the Yahtzee in order to get the points? In other words, if the player rolls five of a kind on the first roll and then re-rolls a subset of the dice to kill the Yahtzee and uses this new result, does the bonus still apply?

2] If the Yahtzee bonus counts instantly, can the person re-roll a subset of the dice with the same result to score subsequent Yahtzee bonuses on the same turn?

I don't see why it would simply count instantly...
For example, if you don't keep a 4 of a kind to go for 5 of a kind (Yahtzee right??) you don't get the score for both, it just wouldn't be fair.

Simple answers...

1. No

2. No

Dogsby

I sent an email to get an official answer. This is what I received:

Answers
1] Yes. You score the values in the final roll only. No score of any kind is accumulated on intermediate rolls.

2] No. See above. Hence, you can obtain at most one Extra Yahtzee Bonus per turn.

Thanks for the help, guys.