Ninja Charms Not Giving Proper Bonuses

The ninja charms do not give the correct bonuses to their respective skills.
After extensive testing with most of the ninja skills, the numbers are very wrong.

For Fire, each charm is supposed to increase the damage of Crimson Fire Blossom by 20% - it seems to be giving a TOTAL of 20%, at the most.
There are similar bonuses for Fire Dragon and Fire Formation as well.

The same trend of tiny bonuses follows Wind and Water as well.

Water is supposed to get 5% per level for Icicle Spear; wind is supposed to get 20% per level for Wind Blade, and so on. All of these bonuses are very small when they should in fact be quite large.