S. 148A: Reassessment-Conducting inquiry, providing opportunity before issue of notice-Income deemed to accrue or arise in India-Royalty-Fees for technical services-Tax residency certificate-Reply filed by the assessee was had not been properly considered-Orders set aside-DTAA-India-Singapore-USA [S.9(1)(vi), 9(1)(vii),148A(b), 148A(d), Art. 12, Art, 226]