The manufacture’s resistance reading could be a rounded off number, or measured with full length tails. Always take a manufactures reading with a grain of salt for it may not be a true indication of the actual resistance of the coil.
And no discredit to the Pico, but these are not the most accurate devices for reading resistances. The devices internal resistance, it’s atomizer even how tight you have clamped down the coil can effect the resistance. And with metals such as Stainless Steel, the temperature of the metal can also effect the coils resistance.
As for your question, there is no answer. We cannot look at the resistance of a coil and give a definite wattage. One could come up with dozens of different ways to achieve a 0.85 ohm coil, all of which will be different and require different power levels to meet our preferred vaping temperatures. What dictates the needed power for a coil is it’s mass and the Specific Heat Capacity of the metal.
