That's due to the 3 year difference. Ghajini released in 2008 while Ra.One in 2011. The business went up in 2011 as compared to 2008.
Ghajini had a distributor share of 59.89cr. The other film which had that sort of distributor share was Gadar Ek Prem Katha in 2001 & it had 57cr distributor share & Hum Aapke Hain Koun which had 53cr distributor share. The only movies to cross 50cr in terms of distributor share. That proves the worth of Ghajini. Ghajini did strong business in single screens that's the reason why the distributor share became the highest ever at that time. Ghajini was released in 1100 screens. Ra.One was a bigger release & higher ticket rates plus the movie was sold at higher price to it's distributors. That's why 64cr distributor from that massive release looks not that good since few lost the money.