It's gray market, not grey market.
Adorama and DJI NY got their original stock from DJI in China. All subsequent stock will be through gray market sources, after DJI decided not to sell the Mavic 4 Pro in the United States, making the original...
Quite simply, a grey market item is something being sold in a country it was not originally intended to be sold in. And for what it's worth, both companies, especially Adorama, have sold grey market items in the past, in particular, cameras and...
It's not that they are profiteering on the price. Assuming they can get any gray market ones, it likely reflects their costs of importing them and paying any necessary tariffs.
Although I have not gone down to draining any battery (of the five I have), a freshly charged battery starting at 99% decreasing to 98% whilst directlly ascending to 176', about a minute into flight, the remaining available flight time showed...