Different situations affect the way FME logs processing time. For example, your translation log might say that FME took 0.1 seconds to process when it actually took 7.0 minutes. The timing part of the log shows the actual time (for example, 10.40 am), the time FME has spent in processing, and the time FME spent processing the previous command.
The actual time taken may not match the time FME spends processing because of external calls such as database queries, which can’t be logged by FME. See How FME logs database information.
Because FME works by pushing features through the workspace on an individual basis (not a group), it is not possible to give exact timings for every individual transformer. Therefore a lot of time doesn't get logged separately but is grouped together under the next function that does support timing.