The final dates for the internal grade 10 to 12 examinations in May/June 2019, and the accompanying broadcast dates for IBP memo discussions are available here. There was a change in the grade 12 examination dates, and the IBP dates have changed as well. Check that you have the correct ones.
Technical science will be written on the same date as physical science in grades 10 and 11; in the case of grade 12 on the same date as physical science paper two.