First of all: If this is SMTP server with multiple cores, try pressing SHIFT-I, that will show percentage of CPU usage per core, instead of per all CPUs
In top it makes sense to show as percentage of single Core, as process in this case cannot use more then one CPU.
With LVE we always show percentage of total, as it is multiple processes that are running.
Second: lveps -d calculates usage over 30 seconds interval.
top resolution is 1 second. All the time that php sleeps, or simply is not running for that user at that time might not be accounted for.