And, more importantly, under what assumptions are you thinking that you can refinance a commercial mortgage to a <4.25% fixed rate for 30 years?  

Up date one side by adding additional bed and bath (the other has already had this done and is in excellent condition)ARV: 475-500KMonthly income: $3200Monthly expenses: $2283 (mortgage, fixed and variable expenses, future assumptions) see below-monthly P & I: $1622- fixed expenses: $340/month (water/sewer, insurance, property taxes)- variable expenses: 2% vacancy ($64/month) , 5% repairs & maintenance ($160/month),  cap exp 3% (96$/month): No property management since we do this ourselves for our rentals.- future assumptions: 2% annual income growth, 5% PV growth, 2% expenses growth, 6% sale expensesBigger pockets tool sheet with above data:Cash flow: $916/monthCash on Cash ROI: 6.65%-7.57% depending on rehab costsPurchase cap rate: 7.15%I know this does not meet the 2% or 50% rule but it seems like a good investment for the area.  

Ask for a copy of all the previous 2 years rent roll statements and compare OpEx and Rev compared to the assumptions.

Normally, in instances like this I make my assumptions using Occam's Razor.Is this a common problem across the industry or did I just happen to run into an anomaly?

Also, if you're not familiar with the market, you can get screwed with location and all the local fees for POS, assumption of violations, demolition of condemned house will be on you.It might cost you much more than you signed for.

Here are the key data points:Park info  Located in Alabama61 lots25 owner occupied homes18 park owned homes (14 currently rented; 4 currently being repaired and should be rented soon)18 vacant lotsAvg lot rent - $160 (unknown what the market rate is but it doesn't sound like there has been a rent increase in at least a year, maybe more)Avg POH rent - $400Expense ratio - seller claims 26% but I'm estimating 35% for the lots and 50% for the POH'sCity water - individually meteredSeptic - good condition (allegedly); a couple were pumped last year, none this year (no lagoon thank heavens)Seller claims gross income $130k, expenses $30k, and NOI $100kI calculated gross income of ~$135k, expenses of $60k (55% on POH and 35% on lot rentals), and NOI of $75kOther infoMom & pop seller, but park is listed with a brokerPark has been on the market for > 3 years (recent price reduction)Greater metro area stats look goodPopulation = 115kMedian home price = $105kUnemployment < 8%Household income > $40kHousing vacancy ~ 15%Closest Walmart is 7 miles awayFreeway is 1.5 miles awayNumbersMy valuation is coming out about $80k-$100k under the seller's asking priceWith conventional financing I'd be hoping for a purchase price of $500k, $100k down @ 6% over 20 years (not sure if this is plausible or not)Assuming that financing, I'm expecting net cash flow of $40k (after debt service)Upside potential is in raising rent and filling the 18 vacant lotsFollowing the same assumptions above, raising rent $50 (if the market supports it) would change NOI to ~$90k and net cash flow of just over $50kFilling the vacant lots could potentially increase gross rent up to somewhere between $150k-$200k, depending on what the appropriate occupancy rate is for the areaWithout verifying any of the above information (haven't offered anything yet so there's a lot of DD left to do), the deal seems to make sense. 

Given the choice, if the state permits it, i would offer a MTM lease, this is the assumption on Tenant owned homes.  

You're starting off in the red, your only option to be the least in the red is to raise rents as much as possible as fast as possible.Using your numbers and some other assumptions such as starting at 900/mo rent I get a 7.24% IRR.  

This is with the assumption that they move out after the first lease, which not many do but seems to be the logic they use.  

However, my analysis was based on the assumption that all my current tenants will for at least a year (which they have communicated to me) .