I can't reproduce any speed difference because JDownloader and Flashgot both max out the connection at about 10 mbyte/s.
Could you create a debug log, see
https://support.jdownloader.org/Know...d-session-logs
Enable Settings->Advanced Settings->Log.debugmodeenabled
restart JDownloader. now start the link normally via JDownloader and wait some seconds, then start Flashgot download in JDownloader and again wait some seconds. Please compare if this run the speed is same/different? Then create log and post the shown logID here.
For me the URLs are nearly identical