There are elements such as Payroll frequency, Overtime and timing that affect the amount paid to the workers in terms of wages payable. For instance, if a company calculates wages every two weeks and the current reporting period ends half way through the two weeks then wages earned prior to this period but not paid are recorded as wages payable. Other aspects include incentives, sales, and variations for such outstanding expenses as taxes or fringes. Timing can also be another cause for variation in the amount required, especially where there are changes in staffing or number of hours worked and therefore makes payroll management an specialized process.

Suggested read: https://accountingbyte.com/what-are-wages-payable/