What cycle days to take Femara for swaying purposes

I was able to obtain Femara from my OB today due to my short luteal phase. He prescribed 2.5 mg daily cycle days 3-7. He also mentioned that some doctors prescribe it for days 5-9 but I can't remember why. What days are suggested for taking it for swaying purposes? I should start my period today or tomorrow.

CD 3-7 is what I recommend as well.

Some people say 5-9 is lower odds of twins, but I have not found that to be the case and feel we see better chance of conception with 3-7.