Somebody forgot to tell Susan Boyle that "Away in a Manger" has a different melody in the USA than it does in the UK. (For that matter, so do "O Little Town of Bethlehem" and "Angels from the Realms of Glory" (which, in the UK, is sung to the tune of "Angels We Have Heard On High" - in fact, in some versions, the third verse of the latter is the first verse of the former).) The version she sang is meant more for choirs, whereas the "US" version is meant more for soloists.
They were also cutting it a little close with the tree lighting, but I think they got it in just before non-padded TiVo recordings would have ended (I pad pretty much all of my recordings by at least one minute each way, so I can't be sure). Whoever arranges the lights on the National Tree in Washington should take notes on how Rockefeller Center does it.