Updated description by EVGENSYPERPRO:
Summary:
Respiration enchantment does not increase the time between taking drowning damage. In the Java version, respiration enchantment increases time how long it takes to take drowning damage again.

Steps to reproduce:

1. Enchant the helmet with a respiration enchantment.
2. Dive underwater.
3. Wait underwater until you take drowning damage.
4. Watch how often you take damage.

Observed results:
Drowning damage deals damage to the player every second (by default you take drowning damage every second).

Expected results:
The time between getting drowning damage will be increased like in the java version (about 3 seconds).

Original description:
When drowning without wearing a piece of armor that has respiration on it, the chance of not taking damage is 0%. When drowning while wearing a piece of armor that has respiration on it, the chance of not taking drowning damage is still 0%. According to the minecraft wiki, the chance should be ((level)/(level+1))% and not 0%.