The test I'm running in that video is for determining the playback latency of external instruments only. Remember, an external instrument is any MIDI instrument not running within Logic itself - so MIDI messages must leave Logic to reach the instrument. This means that an external instrument can be a hardware instrument, or it can be a virtual instrument running in standalone mode.
As I have Kontakt running as a standalone application, rather than as an AU plug-in within Logic, Kontakt is an external instrument as far as Logic is concerned.
The reason that Kontakt's latency is so much higher than the (hardware) external instruments in this video, is that I've set its output buffer quite high - 512 samples from memory. Setting the output buffer to 32 or 64 samples would bring it more into line with a typical external hardware instrument. (Kontakt's output buffer is set from within Kontakt's audio preferences - don't confuse it with Logic's I/O buffer).
As far as your EXS is concerned, Software Instruments have no playback latency, so running this test is not necessary for them. However, if you do run the test, it should result in a measurement of zero samples.
If you're not measuring zero samples, then either your Recording Delay is not set correctly (see the earlier videos for how to set this), the sound you're triggering in the EXS is not trimmed to start on the first active sample, or you have latency-causing plug-ins inserted in your project.
Check those things and see if that corrects the situation.
Glad you're enjoying the videos!