BUG: Converting audio files to 24 kbps or less only converts to 32 kbps

SAB 9.2.4 (Windows)
The resulting audio files converted to MP3, 24kbps, 1 channel in SAB are 32kbps, not 24kbps.
I tried 16kbps with the same result of 32kbps. Changing to 2 channels does not help.

The source file is 320kbps.
I am converting from the Book Collection - Audio Files tab.

convert-audio.bat file:

@echo off
set STARTTIME=%TIME%
for /F “tokens=1-4 delims=:.,” %%a in ("%STARTTIME%") do (
set /A “start=(((%%a*60)+1%%b %% 100)*60+1%%c %% 100)*100+1%%d %% 100”
)

@echo.
@echo *** Convert Audio Files ***

@echo.
@echo.
@echo *** C:! bssa_WIP\Stand Alone Bible Apps_r&d\Audio\bssa_audio\SND12\SND12-GEN-001.mp3 ***
@echo.

@echo on
ffmpeg -y -i “C:! bssa_WIP\Stand Alone Bible Apps_r&d\Audio\bssa_audio\SND12\SND12-GEN-001.mp3” -map_metadata 0 -ac 1 -write_xing 0 -b:a 24k “C:! bssa_WIP\Stand Alone Bible Apps_r&d\Audio\bssa_audio\SND12-24kbps\SND12-GEN-001.mp3”
@echo off

@echo.

set CURRENTTIME=%TIME%
for /F “tokens=1-4 delims=:.,” %%a in ("%CURRENTTIME%") do (
set /A "current=(((%%a60)+1%%b %% 100)60+1%%c %% 100)100+1%%d %% 100"
)
set /A elapsed=current-start
set /A hh=elapsed/(60
60
100), rest=elapsed%%(60
60100), mm=rest/(60100), rest%%=60*100, ss=rest/100
if %hh% lss 10 set hh=0%hh%
if %mm% lss 10 set mm=0%mm%
if %ss% lss 10 set ss=0%ss%
set DURATION=%hh%:%mm%:%ss%

echo Time Elapsed: %DURATION%

@echo.
:End

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