Another gauge corrector--cheaper than MeterMatch, 33.00

I have one of those cheaper ones sitting in the box but I haven't installed it yet. I've just learned to read my demented gauge in which the last 1/4 tank is actually about 13 gallons. I'll put it in at some point.

What's so scammy about the meter match?
It did not work or even come close to working. No recourse cept to eat it