Ok Robert,
so your result looks different! Not sure, if you adapt the parameters right.
I have in total ~517kbit/s (see picture below) which is lower as your setup.
From PlutoFirmware I get a TS rate from 516.759 Kb/s too.
From the screenshot, I see a difference in the q=xxx settings.
I´m using ffmpeg-4.4-full_build.
F1EJP use ffmpeg version 4.3 in his in FreeStreamCoder software.
I also detected, that the versions of ffmpeg may vary drastically!
Above example:
ffmpeg-4.4-full_build → 107MB
F1EJP ffmpeg v4.3 → 65,4MB
That´s what I mentioned earlier regarding "version of ffmpeg"...
It´s all about SOFTWARE, curse and blessing at the same time.
73 de Rüdiger