I can think of several reasons - but the bottom line is that since a HELOC is going to have a higher, variable interest rate, and a DSCR or conventional loan is going to have a lower, fixed rate... it wouldn't make any sense to have the BRRRR sit on the HELOC. 

My market Southern California is very expensive. 

I know personal letters would take more time and cost more money, but I would rather send out less of higher quality then more at lower quality.Having said all of that I would recommend that you tell everyone you interact with that you are a real estate investor and tell them what kind of properties you buy.

These older rowhomes always have some issue that will equate to unexpected expenses. 

. - Construction is more expensive.

:Class A Properties:Cashflow vs Appreciation: Typically, 3-5 years for positive cashflow, but you get highest relative rent & value appreciation.Vacancy Est: Historically 10%, 5% the more recent norm.Tenant Pool: Majority will have FICO scores of 680+, zero evictions in last 7 years.Class B Properties:Cashflow vs Appreciation: Typically, decent amount of relative rent & value appreciation.Vacancy Est: Historically 10%, 5% should be applied only if proper research done to support.Tenant Pool: Majority will have FICO scores of 620-680, some blemishes, but should have no evictions in last 5 yearsClass C Properties:Cashflow vs Appreciation: Typically, high cashflow and at the lower end of relative rent & value appreciation.

Example: purchase price $100kSell price 240kTaxed 140k minus expenses. your cash out refinance is not a consideration for taxes and neither your loan amount as far as taxes go

I have a rate of 3.75% Current PITI is 2180 and other expenses monthly are roughly $200.

Unless you have owned a property a long time, low leverage, lower expenses because the property has been well maintained and cap ex is low - that’s where the magic of cash flow happens.

I am seeing listings sit longer in this market and competition is lower.