[Tex/LaTex] half parskip in koma scrartcl resulting in space at the end of last line before next paragraph

Question

I wrote some things and wanted to have a part of those left aligned and on the same line some words (or formulas) right aligned. I solved that with \hfill.
So sad it is not working on the last line before the end of paragraph when using parskip=half. How can I change that?
For clarification a mwe:

\documentclass[parskip=half]{scrartcl}
\usepackage{polyglossia}\setdefaultlanguage[spelling=new,babelshorthands=true]{german} 
\RequirePackage{mathtools,amsfonts}
\begin{document}
\section{Test}
\paragraph*{Par one}
\(\displaystyle\iint_{G_x}f\,\mathrm{d}G=\int_{a}^{b}\int_{\psi_1\left(x\right)}^{\psi_2\left(x\right)}f\left(x,y\right)\,\mathrm{d}y\,\mathrm{d}x,\hfill f\text{ stetig auf }G_x\)\\
\hbox{\hskip0pt}\hfill\(\displaystyle\iint_{G_y}f\,\mathrm{d}G=\int_{c}^{d}\int_{\varphi_1\left(y\right)}^{\varphi_2\left(y\right)}f\left(x,y\right)\,\mathrm{d}x\,\mathrm{d}y,\hfill f\text{ stetig auf }G_y\)
\paragraph*{Par Two}\hfill\(\displaystyle\iiint f\left(x,y,z\right)\,\mathrm{d}x\,\mathrm{d}y\,\mathrm{d}z=\iiint f\left(u,v\right)\left\lvert\det\frac{\partial\left(x,y,z\right)}{\partial\left(u,v,w\right)}\right\rvert\,\mathrm{d}u\,\mathrm{d}v\,\mathrm{d}w
\)
\end{document}

And here is the result: Please have a look at the second line of Par one.

Answer 1

With one of the parskip options enabled, KOMA-Script will add a space of at least 1em at the end of each paragraph "[i]n order to avoid a change of paragraph going unnoticed, for instance after a page break" (manual, p. 50). This is done -- and can be undone -- by changing the \parfillskip (rubber) length.

\documentclass[parskip=half]{scrartcl}
% \usepackage{polyglossia}\setdefaultlanguage[spelling=new,babelshorthands=true]{german} 
\RequirePackage{mathtools,amsfonts}
\AtBeginDocument{\setlength{\parfillskip}{0pt plus 1fil}}% instead of 1em plus 1fil
\begin{document}
\section{Test}
\paragraph*{Par one}
\(\displaystyle\iint_{G_x}f\,\mathrm{d}G=\int_{a}^{b}\int_{\psi_1\left(x\right)}^{\psi_2\left(x\right)}f\left(x,y\right)\,\mathrm{d}y\,\mathrm{d}x,\hfill f\text{ stetig auf }G_x\)\\
\hbox{\hskip0pt}\hfill\(\displaystyle\iint_{G_y}f\,\mathrm{d}G=\int_{c}^{d}\int_{\varphi_1\left(y\right)}^{\varphi_2\left(y\right)}f\left(x,y\right)\,\mathrm{d}x\,\mathrm{d}y,\hfill f\text{ stetig auf }G_y\)
\paragraph*{Par Two}\hfill\(\displaystyle\iiint f\left(x,y,z\right)\,\mathrm{d}x\,\mathrm{d}y\,\mathrm{d}z=\iiint f\left(u,v\right)\left\lvert\det\frac{\partial\left(x,y,z\right)}{\partial\left(u,v,w\right)}\right\rvert\,\mathrm{d}u\,\mathrm{d}v\,\mathrm{d}w
\)
\end{document}