light times

Haven't we all heard/read that sativa's need light cycles like this: 12/12 11/ 13 10/14 (ect) have run some sativa's (100%) with various light cycles and alway thought that sativa's needed more dark hrs UNTILL I heard this statement: at the equator the light cycle is 12/12 (have been thru...

I am wondering about light times with auto flower does exact light pattern have to followed every day or can it vary from day to day Say it got 16/8 one day and 14/10 the next and then maybe 15/9 do the light times have to be exact or is close good enough