These long intervals are suicidal bollocks put out by ford as a marketing tool.
Look at it this way, why should suddenly belts have twice the life, as there were absolutely NO changes to the material at all they are made from.
Vaux changed from 40-80,000 then there were so many catastrophes they changed back.
The problem isn't generally the belts, it is the tensioner and any idler wheels attached, put simply they don't contain enough lubricant(grease) to go the distance.
Ford rely on the balance of probability that more will be ok than not, but poor sod the ones who are unlucky for this bit of penny pinching.
Up to owners of course, just don't beleive that ford ever tested the interval to see if realistic.
It's like betting some you win some you lose, and lose big time if you do.
Personally I don't even bother finding out what is recommended, and just do any every 3 years or 40,000, whichevers sooner.
tabetha