I updated BIOS to latest version 0030 with the following results:
Now the Boot menu, on BIOS Screen Boot Configuration, is the same as in earlier version 0021 and practically the same as in your post. The start time is 20 sec whit Fast Boot OFF an 16 sec whit Fast Boot ON. So I think the profit on use Fast Boot is quite negligible in case of my NUC configuration mentioned above.
I suppose that the Fast Boot setting I performed properly, because as emerges from help texts to checkbox Fast Boot on BIOS Screen, all necessary optimization (General, USB and Video) are enabled automatically thereafter the Fast Boot checkbox is enabled. If this my presumption is correct, I am sorry that I did not read this help texts earlier.
I would appreciate your opinion of this issue. We can finish this discussion ???