Update 6/10: A commenter got me thinking about this more, and I'm convinced now that there is no problem using the 365-day moving average for the 1-year moving average. See the comments for more explanation. Thanks Victor!
So I've been thinking more about how to calculate the 1-year moving average (MA) of daily data, which is complicated by leap years, which over several decades can leave you astray by several days, which affects the value of the 1-yr MA. (About 10 days over 4 decades, a third of a month.)
Any opinions on this proposal?