They also know about real estate so less likely to charge you extra fees to get an appraisal or BPO because they can estimate the value themselves.

These platforms typically have billing policies where you pay a per unit fee per month to the software and you get regular updates and support each month.There are a number of low-cost platforms available that are able to offer you a lower price by passing along some of the costs to your tenants (payment processing fees, applications, tenant screening, etc).

I am in PA and yes, it is legal to charge late fees to your tenant regardless of Section 8 subsidies or not, provided the tenant's lease allows for them.

The property was rented and generated $160 cash flow after mortgage, taxes, insurance and property management fees were paid.

How much of a credit do they offer at closing to cover the servicing fee?

It likely is out of date as to cost as this info is quite old (my guess is 5 years but it could be longer):- Rent Recovery Service: offers flat fee service starting at $20. 3 letters start at $30.

That is part of the problem with a lot of companies (I am not knocking insula as dont have all the info/facts just stating how the business works), they engage brokers to get them loans and the brokers collect a small fee. unfortunately many of the brokers may be similar to real estate wholesalers - have little to no experience. 

I charged fees for other violations as well but the fees aren't enforceable here in Wisconsin because the lease did not explicitly state what they would be in advance.

This may result in late fees and eventual eviction if not cured within the legally provided time. 

Then pay them a fee for finding the deal and pay them 8-10% of rents to manage the rental(s).