I don't think the implementation of these were thought through. They appear to be in the 4th and 5th slots of the MVP reward table respectively. MVP reward tables are sequential and will not roll for the next item in the table if an item is rolled successfully.
This means you have to fail to roll the first 3 items to have a chance at getting one.
If we assume each item is a 50% chance (they're not), that would be:
50% chance for 1st slot (Ygg Seed)
25% chance for 2nd slot (Ygg Berry)
12.5% chance for 3rd slot (Flower)
6.25% chance for 4th slot (AH Bravery)
3.125% chance for 5th slot (AH Wisdom)
This is a pretty bad system considering one would need tens if not hundreds to get their desired enchant.