I am talking about end of down wind time. Blogs, your procedure seems to be different. Airbus wants you to time from abeam threshold as corrected for wind and start a level turn for finals, when you are about 90 degrees to the runway if correctly vertically positioned only then commence final descent. Purpose of timing is to place you at the same spot on ground for final turn. Basically a visual manoeuvre timing is for guidance. It has to be altered as required to remain visual and keep runway in sight.