Upwork says "You cannot add manual time for the time period you specified." Why?

[#1]

I'm not understanding what the problem is with the Upwork app in adding manual time. I'm picky in who I do work for and this lady I trust and gave me all the information I needed. Though it is a hourly contract and told her it would not go over so many hours. She had a hard time figuring out how to award me the project and I can understand that. So back to the question why can't I add manual hours? Manual time is allowed so I don't understand the problem.

[#2]

Hi Ron, 

Manual time can be added to the current billing period before the Work Diary is locked (which happens at noon UTC on Mondays), and only for intervals that you have not already logged time in. 

The default time settings for the desktop app and Work Diary is UTC. To log hours in your own time zone you may need to switch to your own time zone by selecting Mine from the dropdown timezone menu in your Work Diary. Here's the help article for more information.