What the Acordo did was to legitimize both spellings of the pretérito/past tense, depending on how people pronounce them. In Portugal, we have a distinct pronunciation for present and past tense forms, so for us, the accent has to stay, as a visual representation of that difference. In Brazil, for the most part, there is no sound difference and the accent is absent.
The whole Acordo thing is tricky, because it was intended for the Portuguese language as a whole, irrespective of country borders, so it contemplates lots of possibilities. Of course, it’s then up to each country to ratify and enforce it. Portugal, as the country pushing for it the most, is leading the way…