yes, you are missing the question in your post.
I hold a masters degree (Total - 18 Yrs of education) and applied to AINP with following entries in imm0008 generic form - education section: primary (8yrs), high school (4yrs) ,college/univ (6yrs) and post secondary (0 yrs).
this looks ok, since 8+4+6 = 18, and you seem to have accounted for your bachelors + masters correctly.
as far as first 12 years of education, there is no set standard - if you studied 8 + 4, that's what you did! some write 7 + 5 if that's how it's broken down in their country.
everything looks fine to me, but then, i'm not an immigration officer either :)
these many years of education, and they never taught you to spell 'education' correctly - tsk, tsk (sorry, couldn't resist)