For example, if the property you are buying is a development property, like a small house with a large lot in a developing area, then a small negative cash flow could be okay if you can carry it.

I cannot afford another above the $16,000 which is why I told her $15,000 was the budget.I also stated to let me know of any extra charges that come up so I can watch the number.

I've tried the lower 6-7% PMs and usually you'll either pay mark ups on repairs (what you've noted) or pay extra fees (i.e. labor hours, extra calls) that you may or may not notice. 

I buy real estate but I carry debt which is actually tax deductible, my money works for me.

This extra road frontage now also qualifies my property to be able to be legally converted into a triplex from a duplex.

If your average heating bill is $150, you may not collect enough in the winter months when the bill reaches $225 but you'll collect extra in the summer when it drops to $65.

This would obviously reduce my cash flow on both properties, as I would be paying the minimum HELOC payment plus extra towards the principal to pay it off quickly.

Is it worth the extra work?

Quote from @Jason Baker: I’m A 11th Grader And I’m Committed To Being A Young Real Estate Investor After HighSchool...Just Trying To Seek AdviceThe average person who went to college carries $40,000 in debt. 

I would have to get with the property manager and mimic the exact plans they have set up in the lease, all of which were probably customized by the PM to get a few extra dollars.