Tried a nickel build in my Plumeveil with similar results as the Atomic so I don't think it's the RDA construction itself. Tried the post screw instead of the post hole ... just about everything I can think of.
In the end, don't think it's possible to get the vape I enjoy in the 400-420 temperature range.
That's a 30 gauge, 6 wrap, and 3mm coil build. Reads out to 0.14 ohms on my rDNA. At 22-40 watts in this temperature range my vape isn't warm at all, nor do I get the vapor volume I'm use to at those wattages.
I notice that as soon as I start firing, the wattage drops considerably, flashes the Temp Control screen, and continues to lower the wattage as low as 3 watts until the fire shut off triggers. Not sure if anyone elses does this? Mine does it even if I let the device sit and cool.
So yeah, I'm not sure it's possible to get even close to the vape experience I'm use to while using temp control in the "no cotton charring" temp range.
Another odd tidbit was when I put my Plumeveil on my rDNA (believe the resistance was slightly different ... 0.15 ohms) it never even asked me if it was a new atty.