WA state employment laws, employee's rights to collection final paycheck

Commission/Flate Rate employees: I am a worker that gave my notice and am paid a flat rate for the jobs I have done.(EX. 10 hrs pay for the job regardless if it takes 10hrs. If my employer holds my check until all the jobs are delivered to the customer beyond the state's final paycheck due date, is that legal? It seems like it could go beyond 60 days to file and resolve a complaint, so why bother? - Is this your question? Add additional information