Gentelman,
As i know, the NSE data are more authentic and mostly the closing price issued by NSE is Averaged price of Last 30 minutes, which can't be manipulated by any one. If you are sincire about TA, u must take NSE Clsing price. There are vast difference in Yahoo's Actual last traded price and NSE's clopsing price. Both will effect your results. At the end NSE Closing price is good and reliable.
Thankx
Haresh