Is this directly measured from a 240V circuit? 'cause it's a bit on the high side! Each time I measured voltages in outlets I always got either 120V +/- 0.1V or 240V +/- 0.3V

nope...it's actually a step up transformer...the reason why it is high...if you look in the background....the primary....I wired the 120 volts at the 0 and 100...(instead of 110) and the secondary is being measured at the terminals 0 and 220.....and because I wired the 120 at 100....it makes the voltage that comes out of the 220 HIGHER! That was wired for the LPS from the UK and Europe area...because they were 50 hz.....Max explained that to make the "230" at 50 hz equivalent to the USA 230 volts...it needed to be at a higher voltage...to equal the 230 volt 50 hz....I am not sure how it works..

But I can easily make it 220 volts by wiring it the other way.....

Hmm this must be a better step up than mine, mine only allows you to step up or step down.

This step up transformer is a quality one man! It's HEAVY...with THICK THICK coils too!!!!!

I do know that quality transformers have adjustment taps to be able to get the exact voltage on secondary depending of the primary voltage. The transformers I wired at school had taps for something like 252V - 248V - 244V - 240V - 236V - etc. on primary. It is even more important to adjust them if you connect three separate transformers on 3-phase power!