Volume only goes to 30 when using hw buttons

Hi everyone.

Im using Volumio on a Raspberry Pi 3 with a Hifiberry Amp 2 and everything was working perfectly until i tried hooking up some hardware buttons with the GPIO buttons plugin.

Everything looks OK but for some reason the volume wont go past 30 when i use the hw buttons. If i control the volume via the web interface i can go higher.

Anybody have any ideas? Am i missing something?

Best regards,
Tomas