Does the effect of Pressure stack in Double and Triple Battles?

Question

In Double or Triple Battles, if all of Pokemons in battle with ability of PRESSURE. Will your PP cost more?

Answer 1

Yes.

Pressure causes the Pokémon that attacked the Pokémon with Pressure to lose one additional PP. So in double battles, if you were facing two Pokémon with pressure and you used rock slide, you’d lose three PP: one for using the move and 1 for each Pokémon with Pressure that you attacked. You can theoretically lose up to 6 PP in one turn: if you use a move like surf that targets all adjacent Pokémon, you’re in the middle position of a triple battle, and all three of your opponent’s Pokémon plus both of your teammates have pressure.

Source

Hope this helps!