Firstly IIM Bangalore does not offer FMP in Maths because it does not specialize in Maths. So if you are going for the quantitative field you need to choose an area of interest on your own.

In India Finance has more to do with economics rather than Maths. This is because of the lack of Maths in UG and PG schools. So the research work has a qualitative approach rather than a quantitative one. Here math is just used to express the research conducted and is not for actual research purposes. So based on this information, I have 3 suggestions for you

1. If you are hell-bent on pursuing mathematical finance, do it outside India where the score is higher.
2. Applying in both areas will widen your prospects. The only requirement is that you must do your area-specific courses.
3. Don’t neglect other areas of finance that are very interesting and also quantitative. These include Corporate Finance or Banking.

Based on my suggestions and information you can make a wise decision that suits you the best.