Hi Rohit,
You can use old TDS code with revised rate. For that select the w.h.tax formula and keep blank the rate in w.h.tax code configuration. After that maintain the w.h.tax formula with validity 01.04.2009 with the rate 10%. Later add one more item with validity 01.06.2016 with rate 5%. When you make posting from 01.06.2016 the revised rate will pick and for old posting it will pick 10%.
Regards,
Mukthar