Targeting the enemy's chest gives no Advantage but targeting his legs does?

Say, I'm standing on a high ground, but not by a lot. And when I mouse over my target with my caster's ranged attack, it gives me Advantage based on where I mouse over. If I mouse over his chest, it shows no Advantage on the tooltip. If I mouse over his legs, it shows I get Advantage on the the tooltip. But some testing on my own shows that even if I left click while targeting the legs, I still don't get the Advantage in the combat log.

Is this the same for everyone?

Does this mean that I get the height Advantage in the actual combat only if it says I have Advantage on the tooltip while targeting the centre of the enemy?