Lets Say,
**Purchase Order & sales Order Generation is as follows**
                      Purchase Order(Rs)       SalesOrder(Rs)
    31-Jan-2014 11.00PM      1000                   2000
    31-Jan-2014 10.00PM      2000                   4000

Purchase   Sales
 Jan-2014       3000     6000

Lets Say,
    **Purchase Order & sales Order Generation is as follows**
                     Purchase Order(Rs)  SalesOrder(Rs)
31-Jan-2014 11.30PM      1000                   2000
31-Jan-2014 11.00PM      2000                   4000

Purchase   Sales
 Feb-2014       3000     6000

So According to US, Sales & purchase Order Date is 31-Jan
So According to India, Sales & purchase Order Date is 1-Feb