Apparently, Apple only allows two Lion downloads for the same price or has an expiration time on the first. My download link does not work anymore no matter how I try (option, etc) after three days.
After three installs of Lion on three different computers on day one, after a week's interval the App Store allowed me to install a copy of Lion on two other drives on the first system on one system. That would seem to invalidate your theory.
I have found however the App Store will not happily allow a reinstallation of any app, and I presume that includes Lion, if there are any copies of that app on the boot drive. All traces must be completely removed before anything can be reinstalled.
Perhaps the invisible Emergency Boot partition Lion installs on the boot drive is seen by the App Store Installer and blocking your third download. You might also try booting from the Emergency Boot partition and trying another download and install from there. Apparently that is its intended use.
