@Christopher
I suspect it went something like this,
"yes Mr Senetor this thing only lasts 13 months which gives us plenty of time to ..."
(17 months later)
"Mr Senetor we are getting some amazing results up there we need to play this a bit longer on the funding side"
(2 years later)
"Mr Senetor it would be silly to stop the project now, we never expected this to last this long , honestly, but since it is why dont you fund us till its dies?
i doubt very much "Mr Senetor" would agree to funding a project for 4 years from the word go, but hay if it just kept going then, well, renewing the project life would be much easier.