Repeat tasks and time on completion

Hi - newbie here.

I have a task set for 8am. I set a ‘repeat on completion’ task. I complete the task at 10pm and OF takes the time I complete to be the time of the next repetition. (and the notification shifts to 10pm)

How can I tell OF to repeat at the specified interval after completion but at 8am on that day (OF default)

I would prefer to only specify a date for some tasks - but I believe I must specify a time (pity there are not ‘all day’ tasks as in Calendars)

Thanks in advance for any help…