A common mistake is to attempt to demonstrate in staffing the actual number of employees. Naturally, the positions at the main staff, issues do not arise. As for part-time workers, they are trying to reflect fractional numbers, respectively, a rate of, for example, 0.4 or 0.5 units of the state. This approach is not the most appropriate, as it complicates the work, although it would seem, and allows you to track working hours and payroll employee part-time. Note that the notion of "rate" in the Labour code just yet, so the staffing costs to operate only with integers, that is occupied by the part-time position should be added as a unit.
This option is convenient because even if this position is not one person but two, or you want to hire a regular worker instead of part-time workers, you do not need to edit your payroll schedule. With regard to the perceived difficulties with the payroll, they are easily eliminated properly drafted employment contract for part-time. For example, the labour code provided that part-time cannot work more than 16 hours a week at the rate of 40 hours per week for full-time employment is 40%. Accordingly, intending to appoint a part-time salary or hourly charge, just specify in the contract 40% of the amount of wages for full-time. However, your part-time worker may receive wages equal to the regular rate, if it is directly related to the work being performed successfully. In the case of piece-rate wages is better to use the planned system that allows you to not bind the income of the part-time salary similar to the main employee.
Make a copy of the staffing, and in the notes note how many workers you have running for certain positions. It is better to have the ability to quickly make changes to their marks, as the number of part-time workers may vary.