220, 230, and 240 are for all intents and purposes THE SAME THING. It is called TOLERANCES.
Here in the US the nominal household Voltage is 115 or 117 VAC. But when we talk about the actual Voltage that is delivered to every house it is actually twice that. And two times 115 V is 230 V. But does anyone ever say 230 Volts? NO! The same people who will say the split phase Voltage is 115 V will also say the line Voltage, which is the amount that is split in half to get that 115 V is 220 V.
Now, those are two totally inconsistent numbers. To be sensible we should say 110 V and 220 V or we should say 115 V and 230 V. But almost everyone, even the professional electricians who DO know better will tell your it is 115 V and 220 V. And there is no logical explanation for that.
But back to tolerances and hourly variations in the actual Voltage delivered to a home. I do like to use 230 V so that is where I will start. Now, 10% of 230 is 23 so 230 V, +/-10% gives a range of 207 V to 253 V. Yes, that's a 46 Volt range. And 220 V and 240 V are both completely within it.
And I will bet dollars to donuts that virtually every power company in every country on the planet will tell you that their hourly Voltage will vary by at least that 10%. None of them will be willing to guarantee any better percentage than that. Perhaps they may choose a slightly different base number, like 225 V or 235 V, but all of them are going to be in that general range.
SO, as I said above, FOR ALL INTENTS AND PURPOSES; 220 V, 230 V, and 240 V and even 210 V and 250 V are all one and the same thing. The only differences are due to the time of the day and the load on the generators. They are all 230 V +/-10% regardless of what the countries, the power companies, or the clueless individuals who publish the numbers that are supposed to be what each country "is" say it is.
As for practical operation of equipment, if you find that your area commonly has Voltage readings on the low side, then, by all means do set any power taps in it to 220 V or less. And if your power is commonly at a higher Voltage, do set them for 240 Volts. And if you find that you have a problem with one setting, then, by all means, try another.
Just Go with the Flow (of the electrons/Voltages, of course).