Revenue Procedure 2010-15 updates Rev. Proc. 2008-14, 2008-1, C.B. 435, and identifies circumstances under which the disclosure on a taxpayer’s income tax return with respect to an item or a position is adequate for purpose of reducing the understatement of income tax under section 6662(d) of the Internal Revenue Code; (relating to the substantial understatement aspect of the accuracy-related penalty), and for the purpose of avoiding the tax return preparer penalty under section 6694(a) (relating to understatements due to unreasonable positions) with respect to income tax returns.