OVERALL IPF 4.32. What should be the band??

Ipf and bands are not related. I have seen 4.5 ipf getting B and 4 ipf getting A. It depends on your project manager. Talk to him if you can. Expect B

I got 4.6 and my colleague got 4.64, so he'll be most probably getting A right

IPF is closely but not strictly tied to Band. As per TCS policy managers are not supposed to discuss about Band during appraisal discussion. Also a 4.32 doesnt mean an A.

If you look at the Band - performance mapping. If you're spot on with due diligence and Business as usual , it might still guarantee you C also.

A or B

Expect B most of the projects are considering>= 4.5 for A