--probe-slow when enabled will encode according to the given parameters, then there is no need to encode again when the target crf is computed, as it is already encoded. The file generated in the split folder and the file generated by specifying the crf in the encode file are the same file. Therefore, for target quality mode when --probe-slow is enabled, you only need to copy the files in the split folder that correspond to the calculated crf value to the encode folder. This will reduce the time needed to encode the entire video at once. In a 4+ minute video I tested, it was about 30% less time. (Of course this also depends on the number of --probes)
--probe-slow when enabled will encode according to the given parameters, then there is no need to encode again when the target crf is computed, as it is already encoded. The file generated in the split folder and the file generated by specifying the crf in the encode file are the same file. Therefore, for target quality mode when --probe-slow is enabled, you only need to copy the files in the split folder that correspond to the calculated crf value to the encode folder. This will reduce the time needed to encode the entire video at once. In a 4+ minute video I tested, it was about 30% less time. (Of course this also depends on the number of --probes)