Renovation is typically considered a Capital Expenditure, which must be depreciated over time.Cash flow is certainly not the only metric to use when evaluating RE, but it's one of the most important. 

You didn't change your maintenance or add a column for Capital expenditures, that will cost you an additional $269 a month.

@Lee Stephens make sure to account for the following expenses in your calculations:1) Mortgage2) Mortgage insurance (PMI or MIP) or FHA Risk base3) Property Taxes4) City Taxes5) HOA (Home Owner’s Association) Dues and Fees and Assessments6) Insurance  a) Property Hazard Insurance (0.3-0.45%)  b) Flood Insurance  c) Earthquake Insurance  d) Umbrella Insurance7) Vacancy Rate (usually 8% - the equivalent to one month a year, or 5-6% if multifamily and/or if experienced, if not use 8%)8) Utilities (you’ll have these if your tenant is not covering them and/or during vacancy)  a) Water § Sewer § Garbage  b) Electricity  c) Natural Gas  d) Propane9) General Maintenance (usually 5%)  a) Upkeep § Landscaping  b) Snow removal c) Repairs  d) New Appliances  e) Make ready10) Capital Expenditures (usually 5%, higher is the property is old and obsolete, less if fully rehabbed and all mechanicals and roof are new)11) Property Management (8%, even if you self manage, your time still has value and there might be a time when you'll want to be completely hands off or you'll not be able to do it, vacation, retirement, etc.), including...  

Newer houses have Capex,(capital expenditures).

Operating expenses do NOT include major capital expenditures, they also do NOT include loan repayments.

For me I use 8% vacancy(1 month out of 12),  7% repairs and 8% CAPEX(capital expenditures ie:roof, ac, floors, etc).

Take a look at how insurance, maintenance, Capital Expenditures and other expenses may ruin all of those.

Repairs of 5% and no CAPEX (capital expenditures) roofs, water heaters, appliances.

I bring this up because during the initial years of building ownership, to improve long term cashflow a building owner may decide to make capital expenditures. 

I look for deals with a CoCR of 10% or better.The CoCR formula is pretty simple: Annual_Cash_Out / Annual_Cash_In.Annual Cash Out is typically Rents minus Expenses (Maintenance, Management, Taxes, Insurance, Repairs and Capital Expenditures) minus any Debt Service.Annual Cash In is Acquisition Cost plus Closing Costs + Rehab Expense).So, when I'm presented with a possible rental deal, I assign numerical values to all these variables except one: Acquisition Cost.