"You determine your available spell slots by adding together all your levels in the bard, cleric, druid, sorcerer, and wizard classes, half your levels (rounded down) in the paladin and ranger classes, and a third of your fighter or rogue levels (rounded down) if you have the Eldritch Knight or Arcane Trickster feature."

Right, i should have made this part of my original post. this seems to read that the 3 groups are added together independently before dividing by the appropriate number. That is where my confusion is. I was not able to find any threads out there asking this question... I saw one reference who assumed this was accurate in their post but didn't give clarity.