Payroll: Daily wages, paid monthly


I have a case of paying Salary to Workers based on the number of days worked at a flat rate of say $65 per day.

All the threads on forum suggest using Project Timesheets to calculate hourly payout. The issue we face is that the rates vary widely and its not possible to accurately split daily rate to hourly rates without rounding issues. Since these Workers have a longer term relation, their attendance is managed with granularity of 0.5 days instead of hourly.

Is there a way of managing attendance at a granularity of 0.5 Days and pay based on number of days worked at a flat rate?