What a single stock can do to Sensex?

Looking at the weightage of stocks in Sensex at BSE, I conclude that
Reliance (13.65) > Ranbaxy + Tata Motors + Jaiprakash Associates + ACC + DLF + M&M + Hindalco + Grasim + Sterlite + Maruti + Wipro + Reliance Infrastructure + Tata Steel + Tata Power (13.28).

Thus if all these 14 stocks go up by 3% and Reliance goes down by 3%, the impact on Sensex is still negative. This is not the case with Nifty since Nifty considers Full market cap instead of Free Float. Full market cap of these 14 companies is 1.83 lakh Crore whereas that of Reliance is 1.69 lakh crore.