Blood Magic + Sanguimancy (Blood Mage)

Not sure if a bug or not, but I know someone posted a video saying Blood Magic + Sanguimancy should just erase the mana cost... so if a skill costs 10 mana, with sanguimancy its 10 life and 10 mana, and with blood magic should just be 10 life.

However on trying it this is not the case and it just costs 20 Life, basically paying both costs in life. Just a PSA incase anyone else was going to try this, and its not a bug since I think this is different than how it worked in PoE1:



Top is without blood magic, bottom is with blood magic, as a blood mage.