So, for example, if there is one failed loss on ignition test on the mixture before 1 April 2018 and another failed test after that date, both failures must be taken into account.
Felly, er enghraifft, os oes un prawf colled wrth danio wedi methu ar y cymysgedd cyn 1 Ebrill 2018 a phrawf arall wedi methu ar ôl y dyddiad hwnnw, rhaid ystyried y ddau fethiant.