current rating of transformers

Hi,

If I have a 24 volt, (12V-0-12) center tap transformer like the MPJA
unit.
http://www.mpja.com/productview.asp?product=7846+TR

And isolate the center tap I get 24 volts.

But when rectified, doesn't the current change also ?

There is a note in the catalogue that for this wiring the amps are
1.8x

The catalogue refers to required ouput amps


full wave bridge cap input filter 1.8x to required output amps
full wave choke input filter = required output amps
full wave, center tap, cap = 1.2x roa
full wave, center tap, choke = 0.7x roa


Can someone shed some light on this for me ?

Thanks,

Dave