It's all about taste, anyway. I couldn't imagine running a true 1.6 ohm atty at 6 volts. The dual coils are 3.2 ohm parallel coils, so you just get more heat from two 3.2 ohm coils side by side. Yes, the battery sees a 1.6 ohm load, but it's not quite like
vaping 1.6 ohm cartos at that voltage. The two coils can take the higher voltage when working together.
In a parallel circuit, each 3.2 ohm coil will see 6v. Although the combined resistance is 1.6 ohms, each coil gets the total voltage across 3.2 ohms.
Voltage in a Parallel Circuit