Since this is the fuel (most likely) in our tanks now, are there any
different measures needed for winter storage ?

It was suggested to me that ULS diesel fuel deteriorates more rapidly, so it
was better not to top off the tank, but to fill in the spring with fresh
fuel, and deal with any moisture/water then.

However, my local fuel oil supplier said he hadn't heard anything about a
short shelf life for ULS diesel.

Anyone know anything about this ?