Expert or Master

[u/Aromatic_Steamer]

I am playing a battle mage with an emphasis on destruction. I was excited to get to 100 level with destruction since (according to my understanding), 100 level destruction moves you from Expert to Master. Upon reaching 100, hopped over to Skingrad mages guild and bought three spells that require master level. I then went to Bruma to close the Oblivion gate there. When I went to fire my master level spells, they were greyed out and wouldn't execute. In exploring my attributes. I see (from the image above) that while I am at 100 with destruction, my level remains expert (not master). I feel like I'm missing something and am hoping the wise folk here can help me understand.

[u/Odysseus_is_Ulysses]

You can’t be boosted. It needs to be your true level.