Based on cost alone, all companies would manage payroll in-house. But the decision to outsource payroll is multi-faceted (in fact, most industry analysts advise against outsourcing any business function based solely on cost). Growth-oriented organisations want to actively decrease compliance risk, divest themselves of the responsibility of managing payroll on-premise and relax in the knowledge that they’re working with a solution that will scale cost-effectively in line with business demands.
It’s certainly true that, based on the cost per payslip, with only a few employees in-country your fixed costs per employee will be higher when using a global payroll solution than an in-country platform. However, as your employee base grows, economies of scale kick in and this cost will decrease.