Owen J. Roberts, United States v. Andrews (302 U.S. 517…
“ Where a claim which the Commissioner could have rejected as too general, and as omitting to specify the matters needing investigation, has not misled him but has been the basis of an investigation which disclosed facts necessary to his action in making a refund, an amendment which merely makes more definite the matters already within his knowledge, or which, in the course of his investigation, he would naturally have ascertained, is permissible. ”
