Here I start with the code given in the question cited by the OP.
I don't know the actual numbers are precise, but a \leftskip can be used to compensate for the leftmargin value. I show in this MWE a transition back to the original sectioning system, which must be accompanied by a cancellation of the \leftskip.
\documentclass{article}
\usepackage[showframe]{geometry}
%to lyn preamble from here
\let\svsection\section
\usepackage{titlesec}
\titleformat{\section}[leftmargin]
{\normalfont
\sffamily\bfseries\filleft}
{}{0pt}{}
\titlespacing{\section}
{4pc}{1.5ex plus .1ex minus .2ex}{1pc}
%to here
\begin{document}
\leftskip 1in
\section{Objective}
\noindent
Auditing/Analysis of Operations
\section{Education}
\noindent
B.S. in Management, Rensselaer Polytechnic Institute, Troy, NY, May 1986
Concentrations in Accounting and Management Systems
QPA 3.9 in major, 3.7 overall
\section{A very long section title}
\noindent
B.S. in Management, Rensselaer Polytechnic Institute, Troy, NY, May 1986
Concentrations in Accounting and Management Systems
QPA 3.9 in major, 3.7 overall
B.S. in Management, Rensselaer Polytechnic Institute, Troy, NY, May 1986
Concentrations in Accounting and Management Systems
QPA 3.9 in major, 3.7 overall
B.S. in Management, Rensselaer Polytechnic Institute, Troy, NY, May 1986
Concentrations in Accounting and Management Systems
QPA 3.9 in major, 3.7 overall
\leftskip 0in
\let\section\svsection
\section{A very long section title}
\noindent
B.S. in Management, Rensselaer Polytechnic Institute, Troy, NY, May 1986
Concentrations in Accounting and Management Systems
QPA 3.9 in major, 3.7 overall
B.S. in Management, Rensselaer Polytechnic Institute, Troy, NY, May 1986
Concentrations in Accounting and Management Systems
QPA 3.9 in major, 3.7 overall
B.S. in Management, Rensselaer Polytechnic Institute, Troy, NY, May 1986
Concentrations in Accounting and Management Systems
QPA 3.9 in major, 3.7 overall
\end{document}

leftmarginand\leftskipare likely to be the optimal solution. – Steven B. Segletes Apr 05 '16 at 16:25