Stuck in Veg

In reality, no plants have a 12.0000000000000000000000000000000000000000000000000000000 hours dark period to induce flowering, extrapolate that out and then apply the implications to your situation. Table/floor seeds happen all the time, at every seed vendor or breeder. So if you are being shown a 90% off random floor seed grab bag on where you buy from, then those mistakes are either in the trash (unlikely) or in someone's bag of beans. Even mispacks happen all the time. Even at the commercial level. Unless you have some genetics shenanigans like crossed with some mid for autoflowering or crossed with some 8 hour dark period pfr cycle photoperiods to make a 'semi auto flowering' or a 'fast' strain, then increasing your dark period is the only mechanism to induce flowering. Challenge the notion that the change to 12/12 would negatively impact the autos in the room, what is your math say about that? It will impact them on the change, at face value. The actual ending point once adjusted though, that would only have an impact as far as the lack of proper adjustment on the light fixtures on your end. Luckily, that is the simplicity of viewing the plants from a nuanced understanding of photoperiodism and a DLI view of energy delivery.