The power surge node should be adding flat damage per charges expended and increasing mana cost.
Currently after testing it for a while on the target dummy, it seems to only increase the mana cost. On sorcerer that should be still increasing the damage it does, yet it does not.
I only used 100 stack discharges.
The average damage without the power surge node was 1000.
The average damage with the power surge node was 1000. Which seems odd since it should have added 100 flat damage and it more than tripled the mana cost. Which might mean that the sorcerer passive also does not work.