Yup. Even at the 15-20 /watt range you need an atomizer head that can wick fast enough (ie large juice holes). Don't get hung up on the whole resistance (ohms) thing. You don't need to sub ohm to vape at high wattage. Certain tanks like the Nautilus Mini with the new bvc coils wick like a champ and CAN vape over 20 watts, even at 1.8 or 2.1 ohms. It's all in the coil and head design.
Whenever I crank my Nautilus Mini up to 20+ watts, the first vape is fine, but subsequent hits after that start to lose flavor and start to taste overheated. That's why I always keep it right around 10 watts. It could also be because I am using a 80VG/20PG juice in it. The extra viscosity reduces the ability of the coil to wick it fast enough.
My Subtank Mini handles a 85VG/15PG juice just fine at 22 watts though.