lucas61, it is a trivial matter for the USG to know where you are based upon tracking your movements using your US passport.
The point is, with your US address you don't have problems with SSA, For now, they don't require the proof of life annual letter if you have a US address. It appears to be that simple, for now.
I am a naturalized DR citizen, with a DR passport, I did register years ago with the US embassy well before I was eligible for Social Security, I have a US mailing address and my SSA payments are deposited into a Schwab account which I get free checks and deposit into a DR US dollar account, I do FATCA/FINSERV reports annually, and don't have problems. For now.
For those that have had to reply to this proof of life letter, I think the problem agency is called USPS and how to get that letter delivered to and from the DR with USPS being used in the USA using a forwarder like EPS... That takes more time than you might realize.