Budgeting Payroll Expenses for Multifamily

Curious how those underwriting sub institutional Multifamily assets are budgeting on a per unit cost for payroll. I’ve spent time underwriting larger projects (200+ unit) but recently starting looking at smaller deals in LA that are rent controlled and range from 25-75 units. Is there a rule of thumb or strategy in budgeting for payroll on these smaller sized properties (many don’t have dedicated leasing offices, etc). Are you budgeting for an on site resident mgr and then simply increasing the property Mgmt fee to compensate for additional expense?