Section 270A excludes from underreported income amounts for...

Section 270A excludes from underreported income amounts for which a taxpayer offers a bona fide explanation and discloses material facts; where the return claimed a deduction based on an existing precedent, that explanation was treated as bona fide and no underreporting arose, so penalty under Section 270A could not be sustained. Separately, underreporting for penalty purposes arises only if assessed income exceeds income processed in the return; here the assessed income was not greater than the processed return, so prima facie penalty proceedings were unwarranted and the penalty order was stayed.