Dear Mr Akialok,

I think, the answer what you have given is not completely 
right.As the VA ratting is not going to change in the 
transformer, the max current in primmary & secondary will 
remain same in whatever way you use.
For example: For 1 KVA 220 V to 110 V trafo, Max primary 
current I1=1000/220 = 4.55 A & Max Seconday current 
I2=1000/110 = 9.09 A.
So even if you reverse the source voltage, in any way you 
can not use for more power.
Please reply for clarification.
Sadananda