You are quoting old rules.New rules have a calculated period of Qualified vs Non Qualified usage. 

My biggest rule it to pay off the heloc as soon as possible because the rate is variable and its much safer to be in a locked in mortgage.

Short Answer is yes, via interest tracing rules. 

I saw some properties today, only one of which I thought had potential, but an offer would have to be pretty low to hit the 70% rule which is the goal.

These days, DSCR loans are really the go-to product for investors but many different lenders have overlays and specific sets of rules in their playbook.

They have taken strides to pave the way for ADUs - here’s the implications for real estate investors.It's crucial to understand Raleigh’s zoning rules for ADUs BEFORE deciding to implement this strategy on your current or future long term rental, Airbnb, student housing, MTR, house hack, flip, etc.

.- Tenant Accountability: Many programs have strict guidelines for tenants, and breaking those rules (e.g., property damage) could jeopardize their assistance, encouraging them to be responsible.- Inspections: Some programs require annual property inspections to ensure compliance with their standards, which can occasionally be demanding.- Damage Risk: As with any tenant, there’s potential for property damage.

@John Friendas  it's close to the 1% rule which is good, but I would still run the financials on it. 

It should be producing far better return than the passive s&p to justify the effort.Good luck

Are there any rules, laws, or regulations regarding this?