I'll err on the side of caution and only penalize 1 month.  

Reserves Vacancy (%) 5.00% $ 254.70 Repairs & Maintenance (%) 7.00% $ 356.58 CapEx (%) 7.00% $ 356.58 Management Fees (%) $ - Total $ 967.86 ASSUMPTIONS-5% Down Owner-Occupied Mortgage-3.5% Interest Rate-.75% PMI Rate-$6100 in property tax (from Realtor.com Tax History section)-$2400 in yearly home insuranceRENTS-$1822 for a 2br, 1.5 bath (Rentometer - Average Rent)-$3272 for a 4br,, 1.5 bath (Rentometer - Average Rent)Chicago Realtors, Chicago Real Estate Investors, Chicago Househackers, Chicago Landlords, Chicago Lenders - looking for your thoughts on my deal analysis here.What erroneous assumptions am I making?

There is a lot of erroneous information in the posts above.

Often when I list my flips, I err on the low- mid range, thus getting tons of showing.

His reasoning stemmed from the fact that an erroneous release of lien certificate was filed with the court and somehow the settlement company missed it as well.

That said, here is my two cents...I will always err on the side of caution when it comes to tax sales.

Big chains like Starbucks, Whole foods, Kroger, etc, or mom and pop liquor stores, payday advance loans, laundry mats, smoke shops, etc.Crime rate and types of crimes.Price of properties and day one cash flow at retail price vs appreciation potential.Very important concept to understand thoroughly ... basically the gist is that most cheap things are cheap for a reason, risk and reward are usually joined together via pricing (lower retail prices usually means higher risk), and as a newbie you may not be in the best position to judge and mitigate risk so err on the side of lower risk even if it means sacrificing some potential short term returns to get it ... 

@Erica, it sounds like you are optimistic, so just do your due diligence and try to err on the side of realistic. 

If you want to err on the side of caution, discuss it with your lender and get the green light from them to do so.

So to sum up, don't buy anything before first running the full numbers for the property, and always err on the cautious side :)