Perhaps it's just to encourage buyers during an otherwise slow season (with the holidays coming, etc).
When I bought my TC55 they had 2.9% for 96 months. That was, apparently, designed to flush out the TC55 labeled machines from stock to make way for the T24xx machines...
In any case the 0% for 50 may look good for those looking at Deere (0% for 24), MF and Kubota (0% for 36) compact tractors right now.
~paul