The difference is in "Uploading" versus "Posting". Videos need to go through a "Post" and as well being processed through ffmpeg.exe before it is visible and available to play. I would suggest having them look at that post_max_size again since it is not being picked up by your UNA as you saw in the screenshot. It "may" be that the post_max_size is set at the server level and cannot be over-written. I am not sure. 

You could try calling your php.ini directly in your Cron Job to see if that works too. You would need to change your cron job command to this, assuming your host put the php.ini file in the /public_html directly:

* * * * * /usr/bin/php -c /home2/discove4/public_html/php.ini -q /home2/discove4/public_html/periodic/cron.php