Where did you get $20/month for management? Professional management companies are going to want 8-10% of collected rents. If you plan on self managing I recommend that you budget 10% so your accounting gets used to seeing that money go out the door each month. If you don't do this, you lock yourself into self managing the property or being forced to sell if you want to move.
Everything else looks good. You might even get a slightly lower rate than that if you shop around a bit.
@Aaron Montague How much is "enough" for a condo association to keep in liquid capital? I live 3 blocks away from the property so I plan on managing myself
If your HOA has specific requirements for capital reserves, it should be spelled out in your contract. The money you are putting aside from "repairs" and "cap ex" should cover any reserve accounts.
The other big item you want to check is the financial health of the HOA. Your fee seems low to me, though I know nothing about the complex. Any money you are making could be wiped away if this is the type of HOA that using bonds or special assessments to redo everything and anything. You have some room in your monthly numbers but a 3 year, $350/month special assessment will kill your ROI. If the HOA is in good financial health this shouldn't be an issue.