But if you see the cut off for spot round 2 it was 64194 for ECE 

Yes it is
Not only for ECE but for information technology also it goes around 57000 .
But in spot rounds you can a huge fluctuation in Ranking ( it is just because no Candidate applied for that seat )
Spot round is to fulfill the vacant seats.
So it is the trying of luck and i am sure that you can not depend on spot rounds ( because even a single students who has rank 40000 have filled that seat ) you can see the spot round cut offs 40000 today.
I hope you understand it.
So i am not saying that don't take it as option but you should have a backup also.