Or they were owned by the same owner for a long time, also resulting in low assessed value.  

Case in point, I just bought a house off market for 2/3rds of the county tax assessed value from an 86 year old out of state owner.

BP members, living in Baltimore, MD $20 to $50 thousand dollar row-homes are a dime a dozen; their everywhere within Baltimore City limits and are within my price range.

You have to assess what the property is worth as is, how bad you want it, and decide how hard you want to negotiate from there. 

The asking prices on the package is close to $630,000.Gross rents among all the properties are about $105,000.I haven't walked through the properties, so I am not able to assess their indoor condition, however my initial research suggests that some of the buildings are also a little below market rents. 

With partners, rehabbed couple hundred units of multi-fam and built a dozen or so new 2-4 fams. 

At any given moment, I can see every balance in dozens of accounts, assets, liabilities, net worth, net income, etc. in real-time because......every night (or at least 300 nights per year) I enter that day's charges/deposits/receipts.

I have been doing the same, and in my assessment subleting a  unit makes more sense that actually investing in a similar kind of property.

.§3-3 Should the Property Manager have a disclosed relationship with a property owner, the Property Manager shall review and verify all Tenant applications to determine the applicant’s ability to pay rental fees and to assess the likelihood that the applicant will comply with all provisions of the rental agreement.§3-4 The Property Manager shall accept no commissions, rebates, profits, discounts, or any other benefit which has not been fully disclosed to and approved by the Client.§3-5 The Property Manager shall not mislead a potential Client about the rental market value of a property in an attempt to secure a rental listing.§3-6 The Property Manager shall disclose to his or her Client all pertinent facts relating to any transaction.Article 4: OBLIGATIONS TO TENANTSThe Property Manager shall treat all Tenants honestly and professionally when they are applying for, living in, and/or vacating a managed residence, including through the deposit refund process.STANDARDS OF PROFESSIONALISM§4-1 The Property Manager shall offer all prospective Tenants a written application.§4-2 The Property Manager shall provide all Tenants with a copy of the signed rental agreement and extensions with all addendums attached.§4-3 The Property Manager shall make all disclosures as required by state and local laws and provide the Tenant an opportunity to complete a written condition report within 7 days of moving in.§4-4 The Property Manager shall respond promptly to requests for repairs.§4-5 The Property Manager shall provide a written deposit refund determination to the Tenant within the time prescribed by law after the Tenant has vacated a property.

Each drawer can handle about a dozen files, give or take a few depending on how large the file is.