Larry Clinton At Frankfort, (Central) Indiana
Well your figures are correct for a 100 foot run - however most runs are not that long. And the industry standard for motor and equipment design is normally that their rated output is at 115 Volt AC + or - 10%. IE: The equipment should function properly from 104.5 Volt to 126.5 Volt. Now the power companies standard is at the transformers is 120 Volt +/- 5% or 114 to 126 Volt.
Therefore you will most likely have 4 to 5 times as much variation in your in-coming line voltage than the variation in using 120 volt or 240 to run your motor.

"North American Voltage Ranges

In the US and Canada, 220 volts, 230 volts, and 240 volts are used interchangeably to describe one voltage range that is used to power larger appliances. Similarly, 110 volts, 115 volts, and 120 volts all refer to the one voltage range that is available through the common electrical outlet. The sources of these seemingly different numbers are as follows:

The 220 volt and 110 volt designations are older and familiar terminology, but are no longer used in either product design or by electric utilities in the US and Canada.
The 230 volt and 115 volt terminology comes from equipment design standards. Equipment is commonly designed to operate at 230 or 115 volts plus or minus 10%.
Electric utilities typically deliver electricity, under standard conditions, at 240 volts and 120 volts plus or minus 5% at the transformer.

When one takes into account that equipment is designed to accept voltage variations of 10% at a minimum and that the electric utility regularly delivers electricity within 5% of their standard, there is a good match between the voltage the electric utility delivers and the voltage equipment was designed to use."