A publishing company plans to replace its four proofreaders who look for errors in manuscripts with a new scanning machine and one proofreader in case the machine breaks down. Currently the proofreaders check $15$ manuscripts every week between them. Each is paid $80,000$ per year. Hiring the new scanning machine will cost $5,000$ each calendar month. How will this new system affect the proofreading department's productivity? $($Proofreaders work $45$ weeks per year.$)$