i'm just wondering if anyone has experienced any differences between brands?

Previously I've had the clomid, and another one (can't remember what it was now - Genrx clomphene?) and never had any differences. Always CD24 BT picked up high progesterone which indicated that I'd O'd a week before. This time I used Serophene and CD24 BT had very low progesterone so looks like I didn't O. Could it be that the different brand made me O later than usual or not at all?

Or the other thing is that DS weaned since the last cycle. I thought that would make Oing easier - is it possible that weaning delayed or prevented O?