F1 to H1B COS Travel to India before october


I have a valid F-1 visa and now my employer has filed an H1-B, which is approved. I was planning to leave in July and Stamp my Visa and come back in October 2012. But my employer’s attorney is telling me not to leave the US until October 1st and also have some pay slips in hand. Is there any problem leaving US and stamp visa in India during the period of Aug/Sept and re enter in October?

Appreciate your help.