I just did the exact same thing. On my 2021 MYLR I replaced the OEM Continentals with Extreme Contact DWS06+ 3 days ago. I will keep you posted on my wh/mile change. I had 21K miles on the OEM tires and the wh/mi over this period was 270, exactly like yours. So far I have only about 30 miles on the DWS06+ and am at 280 wh/mi.Replaced the OEM Continentals with a set of Continental 255/45 R19 Extreme Contact DWS06 Plus installed on Monday. Drove 1100 miles this week. Wh/mi has gone from 270 to 300-330 in the mornings. Temperature could be a reason for change because temperature is 20 degrees cooler in the mornings.Round trips of 225-230 miles is resulting in a wh/mi of 290-300. Before the same round trip was 255-270. Driving the same routes and doing the same speed.
The main reason I went with Continental again is because Continental offered me 50% off since my OEM tires were worn out after only 21K miles.