Compare "DateAndTime now asTime" with "Time now" and your computer 
clock.  For me, "Time now" matches the computer clock exactly, whereas 
"DateAndTime now" is off by roughly 15 minutes (and by different 
amounts each time).

This no doubt has something to do with the conversion in #now between 
the millisecondClock and the nanosecond value that Chronology uses 
internally, but I can't see offhand how to fix it.

Avi