Autos and Photos Together, Lighting Question

I have 3 autos and 1 photo in a tent right now, under 18/6 lighting. The autos have started flowering already and 2 are done stretching. So my question is if I switched to 12/12 to have the photo flower also will I be missing out on growth and yield on the autos?

I have read that you can put autos under 12 and 12 light schedule. however it may lower your overall yield. One of the reasons people do this is to run photo and auto together.