Screenshot? Anyway, let's do some maths:

Cloudy Moon Sergeant's Drill Hat (9.8–10.6 buds): 10.2 buds in the middle x 0.9 unusual overpay = 9.18 buds.

Stormy Storm Hat With No Name (2.1–2.3 buds): 2.2 buds in the middle x 0.9 unusual overpay = 1.98 buds.

So, 9.18 + 1.98 + 6 = 17.16 buds. No way 19 - 22 buds. And you don't need to set a range if it's the first purchase of the hat unless you have proof of past offers.

13 buds in unusuals doesn't equal 18.6-21.6 buds, especially with zero proof.