Hi Mihai,
For each SPT function there is a routine that checks if the user has a valid License. This routine is executed only once per MATLAB session.
The license can be generated free-of-charge from NXP website (a step-by-step guide is here).
Depending on your computer setup, that process by take more or less. For example on our Win 7 OSes running on Intel core i7 2.7GHz and 16GB RAM it runs instantly without any lag.
Anyhow, thank you for making us aware of this. For the next release we will try to optimize the this be a single check per MATLAB session.
Regarding your question:
why licensing a free stuff?
It's a company standard procedure that's require such tools to be licenses.
Hope this helps!
Daniel