Date and time field

Hello,

I have a field that is Date and Time here: {VENSCRAPCOST.TransactionDate}

I have a report made that prompt for the date and time.  What I need to have it automatically uses today date and time from 6:35am and until 2:25pm. The time is at 12hr format here.

Also need to the format for the beginning time from previous date and time: 10:35pm until today date and time: 6:35am.

I would like to use this in formula field.

Any help would be appreciated.

Thank you,
Gerald