First i would like to correct you here that crores of packages are bagged by only 1-2 students in a academic year or maybe less.
Now coming to mtech placements , yes a lot of good companies do come for placements and give very good packages to mtech guys. The package is almost similar or more than btech students if you check the average.

Hello!

Yes, IITs are well known for their mtech courses also. Your package depends on how well you do there and how you perform in the interviews. Top companies do approach IITs and select students.