The \@item for \inparaitem is defined as \pl@item in paralist.sty, which steps the list counter, as:
\if@nmbrlist
\refstepcounter{\@listctr}%
\fi
As a solution, making \@nmbrlist boolean as false in \inparaitem will solve the issue:
\def\inparaitem{\@nmbrlistfalse%
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Thank you
Sunilkumar KS