To change the method, as I recall, I went to Deductions & Credits, scrolled to foreign tax credit and opened it in the interview process. Turn down the opportunity to add new information. When you get to the question about the Simplified Method, you can say no. Then it will proceed from there. When I got through, I compared the AMT 1116 forms and my 1040 form. The AMT 1116 changed a little, but didn't change the total foreign tax credit, so none of the entries on the 1040 changed.
Because it said you had to have written IRS permission to make the change, I mailed my return with the correct method. I did not try to e-file with the "wrong" method. If you do, you could save both versions on your computer- I did second one as "Save As" and titled it differently. Then you could show IRS that there was no difference in your tax, as I assume there wouldn't be. Hope that helps.
