How do SET equips bonus stats work? Do they stack?

Let's say you have an equipment set, that gives different bonuses with the number of items you wear of that equips set, like:

2 of 4 items of the set:
- 1watt
- 100avoid

3 of 4 items of the set:
- 400hp
- 400mp

4 of 4 items of the set:
- 5watt
- 10allstat

When you would wear 2 items of that set, you would get 1watt and 100avoid.

Now my question is, what happens when you wear 3 items out of 4 of that set, is the bonus then:
- 1watt
- 100avoid
- 400hp
- 400mp

==OR== (only)
- 400hp
- 400mp

Aka, do the bonuses get stacked? Or do you lose the 1watt and 100avoid from when you only would have equipped 2 items?

Anyone?

The bonuses get stacked.