Human Impr.

Alrighty, unfortunately I cannot approve this yet. At your current mastery levels, you should be LL-A/ML, your human form being below ML rank. Being that this technique is a human power, and your human rank is at LL-A, you are not at the required level to use a tier IV ability quite yet, which are available at ML rank. Also as a side note, because you went substitute shinigami at such a low rank, staff has placed a stipulation that while your character is in his human form, his masteries are locked at average rank.

Hm, looks like I misread the guide. But going back over all the guides, I did notice something else I did not see before. It states that in the improvement guide that in order for a substitute shinigami to reach LL/LL-A, they need to have Zan Spirit unlocked, and it appears you do not. So, unfortunately, despite the fact you have the mastery points to reach the next rank, until you unlock you Zanpakuto Spirit, you cannot reach the next rank up, therefore you are not at the required level to have tier IV techniques.

I am extremely sorry for the misinformation.