In multi-unit apartment investing the rule of thumb is 50% expenses and 50% to debt service. That said even though you show a expense number below 50% I have to assume by looking at this that you lack the experience investing in multi-unit's and don't understand your additional expenses.
I think what’s missing is general maintence, yearly seasonal maintence and replacement maintence expenses.
If you figure half the gross rents at $58,823 and we don’t know whether your numbers figured for a vacancy factor or the properties were completely full during 2008 with no vacancies.
But $58,823 is only $4902 per month to service debt and the cash on cash returns. A new first at $573,750 will require a monthly payment of $4,110 as a 20 year commercial multi-unit apartment loan at 6% due in 5 years.
So what’s left is $4902 minus $4110 = $792.
Now to purchase for 765,000 and finance $573,750 means you had to put down $191,250 as a down payment. Now $792 dollars is all that’s left to pay a cash on cash return on $191,250 plus an estimated $19,125 in closing cost’s so lets see $191,250 plus $19,125 = $210,375 of which $792 dollars is 4.5% cash on cash returns on your hard earned money.
There is no profit per door, there is not even a reasonable profit on your own money, so this investment does not work at anywhere close to $765,000
You really need to look over the whole set of financials and at what the current owners prosent for expenses against a full set of projections based on real cost’s including reserves for major repairs.
Look at the commercial part and property management parts of this forum.