Combining future perfect tenses in a sentence

Which is correct to say?

On Valentines Day 2013 the iPhone will have been for sale exactly half as long as the iPod has been for sale.

or

On Valentines Day 2013 the iPhone will have been for sale exactly half as long as the iPod will have been for sale.

I initially wrote the first one as a tweet, but I reread it and thought it might imply that I'm comparing it to how long the iPod has been for sale from the present date. However, the phrasing of the first seems more natural to me. Was my change correct, incorrect, or are they interchangeable?

Solution 1:

You can make a case for both, depending on the meaning you want to express. The first compares the sale period of the iPhone with the sale period of the iPod up to the time of writing. The second compares the sale period of the iPhone with the sale period of the iPod up to Valentines Day 2013.

If you mean the second, you can probably get away with saying On Valentines Day 2013 the iPhone will have been for sale exactly half as long as the iPod.