Brazilian: getting another student visa in Schengen [closed]

I searched about this a lot, I read the old discussions (including the most linked one How does the 90/18 days rule works, and what I could find about student visas), and I mailed the visa office in Malta getting no response. I'm sorry if this is a trivial question, or it's been answered but in that case I didn't see (or understood) the answer, and I'll be grateful to anybody who will help me out.

Here the matter: A Brazilian who has spent 180 days in Malta on a student Visa, how much time she has to wait to come back, and can this be done on a new 180 days student visa?

My understanding is that it should be ok to re-enter Schengen after 90 days and stay 180 days on a new student visa, but the information is quite confusing, most of it refers just to the 90/180 days rule which is not the case here.

Just to make it clear:

• Brazilian student spends 180 days in Malta on a student visa (English school);
• During this 180 days she does not leave the Schengen area;
• She goes back to Brazil before the visa expires (i.e. she does not overstay her visa);

From what I read here I know that Brazil has a special waiver agreement, but in any case, no calculator I tried (well, I tried two of them), takes into account the 180 days student visa so it already spits out that there are 90 days overstayed.

Again, sorry if this is a trivial question, and thanks again for all the help.