The numbers at the end of the Toad Rally don't seem to match the game. How is the number calculated? Is the real time number displayed without modifiers? Do the purple coins count for an added amount? Do coins collected while Toads are cheering (such as when I have a star) count for more? And what is the bonus score added right before the final tally? Is it random? When are the enemy level multipliers added? And are there any bonuses for doing things besides getting checkpoints and mushrooms?
It looks like the real time number is displayed without modifiers. Purple coins DO count, (I believe 10). All coins are the same. The bonus score is calculated from the number of Toads you have. It is not random. The enemy level multipliers are added as you are destroying them. (For example, jumping on a Goomba. There are bonuses when you step on multiple enemies at once. (e.g. jumping on 3 Goobas in a row gives you 1, 2, 4 coin respectively in the order, plus the enemy bonus level.) Hope that answers all your questions.