Welcome to our Forum and thanks for your question.  Thanks as well for your confidence in our service.  I'll do my best to help.  Your results are absolutely conclusive with no need whatsoever for further testing related the encounter of concern.  In general 4th generation, "duo" tests alone are more than 99% conclusive at 28 days - in fact, neither or us on this forum have ever seen or heard of someone whose test became positive after 28 days.  When combined with an RNA test however, the results are absolutely conclusive. 

False positive blood tests for syphilis are quite frustrating.  All blood tests have occasional false positive and for syphilis tests, the rate is a bit higher than for many other tests (including the tests for HIV).  While certain conditions such as chronic inflammatory diseases like Rheumatoid arthritis, or chronic infections are somewhat associated with falsely positive tests for syphilis, in most persons it's simply bad luck.  In more than 85% of persons with falsely positive RPRs the tests are reactive at titers of less than 1:2, as is the case for you.  In some persons false positive tests go away on their own, in others that can be a lifelong source of frustration.

I hope that this information is helpful. EWH

Hepatitis following oral sex is not a concern except if you practice both rectal and oral sex in a sequence which might lead to introduction of hepatitis A virus from the rectum into the mouth and throat.  While some internet sites list the possibility of acquiring hepatitis B or C from performing is totally theoretical,  Textbooks do not acknowledge the possibility and I have never read a research paper in which oral transmission of hepatitis  or C has been proven.  I would not be worried about hepatitis.   There is no transmission of hepatitis (or HIV) ever proven from receipt of oral sex. 

I hope this further explanation is helpful.  I urge you to accept your false positive as bad luck and not a manifestation of some other STI.  EWH