Mutual fund average basis rule - when can you revert to cost basis (actual cost of each share)?

According to Pub 564, once one selects an average basis method for a particular fund, one must continue using that method until the IRS gives its approval to change it. Most everyone believes that if one liquidates all
positions in a given fund (possibly in multiple accounts), then one can start over with whatever method one chooses when one starts a new investment in that fund.
1. Any citation for that rule? A quick search, at least, didn't turn up a source.
2. Does one have to liquidate IRA accounts as well? One might think not, but early this year the IRS put out a Revenue Ruling on wash sales, that says that the wash sale rule applies (admittedly, a different rule) even if one sells in a taxable account and repurchases in an IRA. Revenue Ruling 2008-5. So I don't have any idea about the interplay between IRAs and taxable accounts in the context of average basis accounting.
Mark Freeland
<< ------------------------------------------------------- >>
<< The foregoing was not intended or written to be used, >>
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a site by and for consumers of financial services and advice. We are not affiliated with any of the banks, financial services or software manufacturers discussed here. All logos and trade names are the property of their respective owners.

Tax and financial advice you come across on this site is freely given by your peers and professionals on their own time and out of the kindness of their hearts. We can guarantee neither accuracy of such advice nor its applicability for your situation. Simply put, you are fully responsible for the results of using information from this site in real life situations.