Understanding his powers
As far as Lex's new abilities were concerned, so long as they were on the list of expected abilities gained in the process of cultivating Regal Embrace, the cultivation technique gave Lex information on them.
For Intuition, however, even if the cultivation technique failed to provide him with an explanation, he would have known. After all, it was in the nature of the technique itself to provide Lex with information about anything related to himself.
For example, currently his intuition was telling him that he should thoroughly master controlling his spirit and soul sense before exiting his room, at least in the guise of the Innkeeper. When Lex's thoughts went to why it was so important he should not appear as the Innkeeper before mastering those abilities, his intuition pointed towards the Host Attire.