1. When the wall time and cpu time rows has different units
e.x. running multiple cores
2. When duration is around 1E3 or 1E6 microseconds
printf("%6.2F", 999.995) gives 1000.00 which is 7 digits
In particular, this allows `true && time true`, or `true; and time true`,
and both `time not true` as well as `not time true` (like bash).
time is valid only as job _prefix_, so `true | time true` could call
`/bin/time` (same in bash)
See discussion in #6442
