Line voltages are nominal, that is to say they vary. Variance of only 10V is not significant. Line voltage can vary that much from place to place anyway. Here in the US for example it is all 110, only sometimes quoted as 120, just as sometimes 220 is quoted as 240. It is all the same voltage, only it seems no audiophiles are able to understand this and so freak out over a few volts here and there.
Think of it this way. Your typical tube amp has outputs for 4ohm and 8 ohm. They all come off of the same transformer, just different taps with different numbers of turns. You can run the speakers perfectly fine either set. One usually sounds a little better. The situation with your power transformer is exactly the same. You can run it either way. You can even do just like the amp taps and try it both ways and use the one that sounds the best.