Helm of Suppression

I have an empowered Helm of Suppression on the board. My enemy plays Fizz, Trickster and wants to play a spell. What is the total cost the enemy must pay to play the spell?

. Fizz will first ignore energy costs, hence setting the base energy cost to 0 (356.1.b.2.) [ -> . Then Helm's addition to cost is applied after (356.3.) [ -> ].