Vodafone is slow with their integration. In Kolkata Vodafone had 10Mhz band 3 for LTE and Idea had 5Mhz band 3 for 2G. After integration they've started using full 15Mhz in band 3. Similarly, 5Mhz of band 1 has been used for LTE, with the rest for 3G, God knows why. Both Vodafone and Idea 2G are now on 900Mhz.
So I guess once they take their own sweet time for integration, full spectrum in band 3 will be deployed in TN