After reading the documentation: http://momentjs.com/docs/#/displaying/difference/, you have to consider the diff
function like a minus operator.
// today < future (31/01/2014)
today.diff(future) // today - future < 0
future.diff(today) // future - today > 0
Therefore, you have to reverse your condition.
If you want to check that all is fine, you can add an extra parameter to the function:
moment().diff(SpecialTo, 'days') // -8 (days)