Joomla 1.7 Module positions top10-12 pressing into top7-9 area

Hei

I want to have one module taking 50% of space, i assign it to top9 lets say.

Then i assign two modules to top10-12, i want them both to take 25% space, but they press into my first modules area, so every module has 33%.

By the modules area map, they shouldn't do this..... or am i understanding it wrong?
How can i fix this.

I want them to divide just like left_top, top and right_top, only in different order. Should i redraw these positions?

Thank You