Here’s my experience.... in a field of photo periods, 2 turn our to be autos by a VERY BIG surprise...I never bought them but they were in there. So while the others were enjoying the veg at 18/6 for 7 weeks, the autos had no choice when the 12/12 switch occurred. The autos were already showing bud sites and pistils....long story short.... they all turned out fine...the autos simply got harvested about 5 weeks before the photos. Here’s the problem though, the yields on those autos would have been better if those lights could have stayed on 18/6 for the entire grow period.
because of the short time to harvest, if a photo period plant has to be discarded, an auto could be germinated and placed in that tent to fill a gap within a small window of time and still present a successful yield.