It's based off of actual in-game play time and nothing else. On average you're looking at approximately 50 to 55 minutes per tier. You will not level it up any quicker playing Blackout either. And you will pretty much not level it up at all playing Zombies. So quick modes like TDM or KC are your best bet. Maybe chuck in the odd DOM game if you're bored too.Whats the best ways to level up your black market tiers in BO4? Im tryna grind but need to know what works best to level up quickly.