Query on 44da

It is true.  It is optional to claim 44DA or 115A.

It means that either you can choose 44DA or you can choose 115A. You cannot choose both.

If you apply 44DA, it will be taxed as business income and will be taxed as per normal slab rates. But if 115A is applied, it will be taxed as per rates mentioned in 115A. 

As per sec 115A, it means that where 44DA is applied, you cannot tax at rates specified in 115A.

Hope you get it what I mean

Section 115A does not apply if non resident or foreign company has PE in India so in that case section 44DA shall be applied. In other cases Section 115A shall be applied.