Not sure which location u r from. Here in India, Hyderabad we complete all the steps before we apply for Visa, which also includes medical exam. When my dead line for TRU has crossed, I did not want to give any opportunity for the Visa guys to reject my app. So I took the initiative to email and fax the new offer letter of May to the embassy. Tomorrow I am planning to send the hard copy of my new offer letter along with a note through VFS to the embassy.
I have been informed by my consultant that when ever the Visa gets delayed with out any reason and if u feel the documentation is perfect & complete authenticated, it is good to fax them a note every alternate date, giving them all the details like when u have applied, passport no, tracking no, univ name, joining date etc. According to the consultant, when ever there was delay in Visa & when students have faxed the embassy, there was a result with in few days of time. So I am hoping the same for me... as well as... all you folks who are waiting for Visa just like me.