Start here: why sparse grafting is the right approach, not a shortfall
Scar tissue has a poorer blood supply than normal skin, and grafts depend entirely on that supply to survive the first days after placement. Yield is therefore lower, sometimes considerably, and packing grafts densely makes this worse rather than better, since they compete for what circulation there is.
Experienced surgeons place sparsely, accept a partial result in the first session, and plan a second session once the first has improved local circulation. A surgeon proposing a lower graft density than the visible scar area appears to need is applying this principle correctly, not delivering less than you are paying for.
This is worth saying plainly because it runs directly against how most patients instinctively judge a quote. Faced with two proposals for the same scar, one offering more grafts for a similar price and one offering fewer, the natural instinct is to assume the higher number represents better value. For scar grafting specifically, the opposite can easily be true: a surgeon offering a lower, more conservative number who clearly understands why may well deliver more surviving hair than one who packs the area densely without that understanding.