Clearblue Advanced Digital OPK

Just started using this for the first month.  The instructions said most women have two days of "high fertility" results followed by "peak fertility".  I am on my 3rd "high fertility" day.  Should I be testing in the afternoon also?  I don't want to miss my "peak" because my husband doesn't want to have sex very often - so I need to time it at the most optimal time.  Any experience with this?  Thanks!