How is it possible that IIIT Bangalore's mTech CSE Average package (27.5LPA) is greater than IIT Guwahati CSE Average package (27.04LPA)?

The difference in the packages is due to the inflated figures released by the institutes. For instance, Microsoft offers 42 LPA packages but the actual in-hand salary is only 13 LPA. 

Also, IIIT Bangalore has no core job offers whereas, in IIT Guwahati, you can also explore other domains apart from IT like finance, consulting, analysis, data science, etc. It is exactly why Inthunk placements should never be the criteria to judge the credibility of an institute or program. Rather, we should start considering in-hand averages.

Another possible reason for IIIT Bangalore's better placements is the excellent research-focused culture that provides great knowledge and scope.