DMR publishes three schedules and they give different crops. Soft airing brings air to 19 C in 48 hours and 17 C in 72 hours, with carbon dioxide falling from 4000 to 1000 ppm over those 72 hours, and gives smaller, better spaced flushes. Severe airing takes air to 15 C as soon as possible and carbon dioxide below 1000 ppm in 12 hours, for a heavy first flush. Moderate airing sits between them.
Pick by your labour and your buyer, not by habit. Four DMR documents give four fruiting bands between 14 and 18 C, so do not chase one number.