While I was wrong about Line 14 of the Table doing that percentage, I just don't understand WHERE you are interpreting that about the interest. 

NOWHERE does it say what you are thinking it says.  NOTHING you have cited shows that.  The only think you have cited is the order for the payments for PRINCIPAL (and you are correct about that).

WHERE do you interpret the the INTEREST is allocated that way?

I really hope you haven't been doing this on clients' tax returns.