I have read people suggesting Bandh after expelling air from your body(as much as you can). Some experts suggest - do bandh after you have filled air inside.
Hi Aditya, I cannot tell you what the difference is in terms of effect..
I can tell you though, that in the AYP book Yogani says that holding your breath with your lungs empty is not natural.. it is done during uddiyana/nauli and sometimes happens in automatic yoga... however in our AYP practices we do not hold our breath with our lungs empty.
I am sure the experts out here will let you know what the effects of full and empty lungs are.. if any.