Hi All,
Thank you very much for your replies. after some research, I have found that the number of added records can be more in case where there are start routines and global routines etc. because each record from source can be split into several records by the time it reaches the target.
In 7.x transformations, several routines are written at the 2nd part of global routines in form structure and the forms are called at the field routine level. so many new routines contributed to the increased added record count
I compared data from many different angles and it was a perfect match without any discrepancy.
Thank you all,
P