well in BD you add up the number of marks you get (including collective) then divide by the maximum number of points you could get and x's by 100, and VOILA!!!
in BE they work out the score by the taking the percentage you had got of the full marks away from 100 so the lower the percentage the better. ie in BD if you won with a percentage of 65% this would be converted to 35 points in BE and then the more faults you get in x-country and showjumping are added to it.
85/100 is 85% in pure dressage but seeing as it's penalties in BE, you need percentage bad marks-or the amount of percentage that you lost. So just do 100-85= 15
Confusing isn`t it? I can work out BD dressage easily now using PG`s method, so I don`t even think about the BE %. Probably next year I will need to, so I`ll leave it til then...