AM I missing something about the simulator? The VAB seems to not simulate anything beyond "1.00 Years, 407.00 Days, 1.00 Hours, 27.00 Minutes, 35.38 Seconds". When I fill my ship up with Snacks and FreshAir, it eventually maxes out to that number and goes no further. Even if I then triple my FreshAir supply, it won't go up.
I can also now confirm toric5's observations. While the simulation updates correctly for FreshAir when I turn on the converters, it does NOT update for soil>snacks converter. I just docked a resupply mission to my spacestation and I still only have 142 days on snack use remaining according to the in-flight estimation, whether I turn the converters in my Hitchhiker containers on or off. This DOES seem to correct itself when returning back to the space center.