here is what matters on a biological level, very specifically -- length of uninterrupted dark period.
As long as you don't give the plant 10 or more hours of uninterrupted darkness, the hormonal balance won't cause a shift from vegetative growth to flower gowth. So, if you want to turn the schedule on its head, go with a longe light period to start that new cycle. *if very intense light involved, may want to dim or otherwise reduce power as the plant can only handle so much per day. (or any other arbitrary increment)
12/12 is 'safe' ... don't think i've heard of anyone having a problem with 13/11. 10hours is a rough estimate of when these hormonal changes occur... there may be variety between species and even within a species, potentially. So, just make sure it doesn't get near 10 hours of uninterrupted darkness, and you won't confuse it.