Especially when you are new to the game, swinging for the fences leads to lots of strike-outs.

The first thing that strikes me as odd is the fact that you got assessed a flat special assessment.  

I don't like the lack of control and the entire thing strikes me as a legalized gambling operation where the house has their thumb on the wheel.  

*USING THE INFO GIVEN* use this for example only as there are various methods to come up with a offer/purchase price.21 units total gross yearly income 201,600, 5% Vacancy, Expenses PM 10% of gross, Taxes 32k year, Insurance 16k year, maintenance 10 % of gross, Common area utilities 1,500 yr:(INCOME - EXPENSES = NOI) 201,600 - 99,900 = 101,700NOI * CAP RATE 10% = 1,017,000 (strike point)(strike point - 10% = offer) 1,017,000 - 101,700 = 915,300

You don't have to keep those tenants in for the long haul if you want to fix up the place a little and raise the rent and they don't want to pay more.If you two agree on a price you like, strike the deal.

Let me guess - you live in a municipality where they have a "three strikes" ordinance - three police incidents and you are no longer allowed to have a landlord license.

As for the ultimatum, it's noted I'll keep collecting rents for a few months to see if he 'strikes' again.  

I'm picturing an advertisement with you in a black Secret Service type suit, wearing dark shades, and striking a James Bond or Charlie's Angels type pose while holding one of those guns with the flags that says "BANG"....except of course yours would say:

You will need to hang your license under a more experienced broker for two years before you can strike out on your own, unless you are an attorney already.

They also get a flat fee every month for management, not a percentage of rent collected, so they make more money if they put bad tenants in my property, which strikes me as a huge conflict of interest.