AS far as I know EPO helps to produce more EWCM rather than lengthening your luteal phase - so you take it in the two weeks prior to OV and then stop once Ovulated.
Its fine to carry on with 100mg of the vit b6 after OV.
If you are looking to lengthen your luteal phase I know some of the girls use agnus castus - I am sure someone out there will be able to give you more info.
Good luck sweetie.

Rx x x x