I guess it is a trade off for unsuitable symptoms in women such as hirsutism and hair loss or fertility problems due to PCOS with having the cortisol levels you should have to prevent the former. 

The important thing to remember is that no two people are alike and therefore med’s need adjusting if they are not making you feel ok.  I know what I would be doing in the latter half of the month if I had problems, but that’s me.  The med’s they prescribe would be a tad higher than your normal daily cortisol levels anyway, so would with any luck be adequate to cover you throughout the month.  Perhaps the secret to having your med’s controlled perfectly is to have any adjustments of med’s firmly based on what you blood levels are reading in the week before your period is due.  Obviously that is when you would have higher 17 OHP and where they should adjust things to the right levels.  That way it covers you the whole way through the month.  Who knows?