Honestly why is this even a question, no one is going to ding you for wearing your best, aka blazer n tie. If they do, they r retarded n u shldnt even be joining them.

U r going for a job interview so you shld be trying to set up the best impression, stop trying to lowball on your own attire, there is no benefit in doing that other than the convenience of not having to carry arnd a blazer, but srsly?

Unless the HR specifically tell u to come in a specific attire, then u do that. If not, just wear blazer n tie. Nuff said, no need to keep thinking.