Paul,
I don't know if I can really justify two except in retirement I have a goal of simplifying tasks I like doing but don't want to spend too much time doing and to have equipment that can easily handle the task. It is the same reason that installed a 40 KW diesel standby generator a few years ago because dragging a portable gas generator from the barn to the house in the snow isn't that much fun anymore
The Deere 955 does a nice job of mowing but you do have to slow down quite a bit under some conditions to avoid partially cut strips from the heavy weight on the front tires, the engine has plenty of power to go at any reasonable cutting speed but even with high lift blades you have to slow down. I expect the F series will cut a bit off my mowing time and I will enjoy leaving the loader on the 955 except maybe for using the tiller where there are a few places that clearance/turns get pretty tight in part of the garden area.
The dealer is involved with a farm progress show this weekend so I will get an update early next week for the delivery date. I am glad it isn't today with a high of 33 and high winds.
Rodger
IMHO the word "justify" does not generally apply to those of us are old, and retired.
After retirement: If you want it, and can afford it......GET IT!
Under those circumstances, there should be absolutely no need to even attempt to "justify"!