At .2 Ω with a fully charged battery at 4.2 volts, you're pulling 21 amps and 88.2 watts. The LG HE2 batteries are rated at 20 amps so you're going over their rating. .3 Ω drops it down to 14 amps which allows you a safety margin. I wouldn't go below .3 Ω.
You also should be aware that any ohm meter is not 100% accurate so please factor in the safety margin.