Acronyms only shown in Index when used twice

Question

The solution to the original problem was resolved here: Acronyms sorted alphabetically in Index , in which I was trying to include acronyms in the index every time the command \gls{acronym} was used. The provided code worked very well, however, I noticed the acronyms are only displayed in the Index when used twice or more (MWE and output below). I have a long list of acronyms only mentioned once throughout the text and I need them all to be displayed in the Index. Any ideas?

\documentclass[11pt]{article}
\usepackage{makeidx}
\makeindex
\usepackage[acronym,toc,shortcuts]{glossaries}
\makeglossaries

\renewcommand*{\CustomAcronymFields}{%
  name={\the\glsshorttok},%
  symbol={\the\glsshorttok},%
  text={\the\glsshorttok\protect\index{\the\glslongtok\space(\the\glsshorttok)}},%
  plural={\the\glsshorttok\noexpand\acrpluralsuffix\protect\index{\the\glslongtok\space(\the\glsshorttok)}},%
  first={\the\glslongtok\space(\the\glsshorttok)},%
  firstplural={\the\glslongtok\noexpand\acrpluralsuffix\space(\the\glsshorttok)},%
  description={\the\glslongtok}%
}

\SetCustomStyle

\newacronym{cd}{CD}{compact disk}
\newacronym{cho}{CHO}{chinese hamster ovary}
\newacronym{bhk}{BHK}{baby hamster kidney}
\newacronym{hek}{HEK}{human embryonic kidney}
\newacronym{hgh}{HGH}{human growth hormone}
\newacronym{scfv}{scFv}{small chain variable fragment}
\newacronym{pi}{pI}{isoelectric point}


\begin{document}
\noindent
First\index{first} use of \gls{cd}\\
subsequent\index{subsequent} use of \gls{cd}
, and
\gls{cho} and
\gls{bhk} and
\gls{hek} and
\gls{hgh} and again \gls{hgh} %used twice and displayed, likewise \gls{cd}
\gls{scfv} and
\gls{pi}.

\printglossaries
\printindex

\end{document}

Answer 1

Sorry, I forgot to add \index to the first and firstplural keys, which is why the terms on first use weren't being indexed. Here's the corrected MWE:

\documentclass[11pt]{article}
\usepackage{makeidx}
\makeindex
\usepackage[acronym,toc,shortcuts]{glossaries}
\makeglossaries

\renewcommand*{\CustomAcronymFields}{%
  name={\the\glsshorttok},%
  symbol={\the\glsshorttok},%
  text={\the\glsshorttok\protect\index{\the\glslongtok\space(\the\glsshorttok)}},%
  plural={\the\glsshorttok\noexpand\acrpluralsuffix\protect\index{\the\glslongtok\space(\the\glsshorttok)}},%
  first={\the\glslongtok\space(\the\glsshorttok)\protect\index{\the\glslongtok\space(\the\glsshorttok)}},%
  firstplural={\the\glslongtok\noexpand\acrpluralsuffix\space(\the\glsshorttok)\protect\index{\the\glslongtok\space(\the\glsshorttok)}},%
  description={\the\glslongtok}%
}

\SetCustomStyle

\newacronym{cd}{CD}{compact disk}
\newacronym{cho}{CHO}{chinese hamster ovary}
\newacronym{bhk}{BHK}{baby hamster kidney}
\newacronym{hek}{HEK}{human embryonic kidney}
\newacronym{hgh}{HGH}{human growth hormone}
\newacronym{scfv}{scFv}{small chain variable fragment}
\newacronym{pi}{pI}{isoelectric point}


\begin{document}
\noindent
First\index{first} use of \gls{cd}\\
subsequent\index{subsequent} use of \gls{cd}
, and
\gls{cho} and
\gls{bhk} and
\gls{hek} and
\gls{hgh} and again \gls{hgh}
\gls{scfv} and
\gls{pi}.

\printglossaries
\printindex

\end{document}

The index is now: