Today, I am told by A/C serviceman that the thermostat setting should be 72 degrees regardless how high the outside temperature is. The reason is: every time the unit kicks on or off, it will use 240 volts, and a low setting will make A/C run non-stop, thus will save electricity. Any truth to this? He also says that the setting for winter should also be 72 degrees! If he is right, how about EPA recommendations (78 degrees in the summer and 68 degrees in the winter)? How about some units that will freeze up if the setting is too low (70-73 degrees)? I need some professional advise. Thank you.
By the way, a low setting will make the unit run non-stop, won't that damage the machine in long term?

I recommend like you stated 78/68. Every degree below 78 that you lower the thermostat will cost you 8% more in cooling cost. If 78 is not cool enough I would not set lower than 75.The unit running longer will not hurt unit. They are design to run. There is another theory that the thermostat should only be set 10 degrees lower than the ambient for cooling

Absoluty agree with Esquire1, to state that an air conditioning unit will cost less to operate if run continuously, then allowing it to cycle at a higher temperature is totally not true and the statement of using 240 volt, it uses 240 volt any time it is running not just on start up.
Get a different a/c co. in the future.