Sec 48 proviso 1

It means that the calculation process of converting into foreign currency and reconversion of capital gains from such investment, apply only in case of non residents.

My doubt here is , Assume MR . A being Non resident invest in shares of indian company using USD repatriated. On sale of such shares, whether 48 proviso 1 is applicable, if no reinvestment made?

It is clear that on reinvestment of such sale proceed, sec 48 proviso 1 will apply.

Yes.

No, reinvestment is not the criteria for this proviso. It means the same process will apply on reinvestment too.