Later on we're planning on charging managers/companies that want to use this as a tool to manage multiple teams and employees. We'll never charge the users that are using it as an individual account.
How does your software fit in with the purpose of timesheet software? I know they're not the same, but people have to enter this information for timesheets to bill clients. I know that people put that off all the time, so if they had to do this as well it would be a nightmare. How would you convince a company that already uses timesheet software to also use your software? I see one or the other becoming a repetitive task and the odd thing out that everybody starts to hate.
I did use something like that at the last company I worked for. Something we're looking into (probably more long term) is building out an API that can play well with others.