They're not tiers. They're different methods for different cases.
FUE, DHI, Sapphire — these names get sold as if they were tiers of quality. They are not.
All of them extract the follicle on the same principle. The difference is in how the channels are opened and how the graft is placed.
Sapphire uses sapphire blades instead of steel, so the channels are finer and heal faster. DHI implants the graft directly with a pen, without opening a channel first, which helps with high density and with planting between existing hair.
No technique is better than another in absolute terms. The choice depends on the degree of loss, your hair type, the state of your donor area, and whether there is existing hair that has to be protected.
If someone tells you one technique is the answer for every case, that is a sales pitch, not a medical opinion.
What does your case actually need?
The video explains the general rule. The number that applies to you is settled after an examination — the grafts your case actually needs, not a figure quoted before we have seen you.