4 plex analysis - review my numbers

[Craig Montesano]

4 - 1 bedroom apartments
asking price - $110,000

Monthly rents total - $1,575
NOI - $18,900

Expenses
Taxes - $1,140
Ins. - $1,200 (still waiting on quote)
Water and Sewage $4000
Mgmt fee $1900 (if I use one)

Expenses - $8,240

Profit before debt payment - $10,660

selling price of $95 - with 25% down and a 4% rate - P&I would be roughly $340

10660 / 12 months = $888 - $340 is $548

Which in turn at $95 selling price gets me $137 / door.

Using the 50% rule ...If I am doing it right

$18900 / 2 = $9450
$9450/12=$787
$787 - $340 = $447
$447/4 = $111 / door

There are currently 0 vacancies and tenants pay all utilities.

I don't believe I forgot anything??

Any help or insight is much appreciated. Thanks!