Hi Steve,
The Upload field is designed by Joomla core, and it will show the value of PHP variable: upload_max_filesize of your PHP system even you can change the Edocman Configuration to increase value for field: Max Upload to 32 MB. And even you change value of Edocman configure option: Max Upload to 32 MB, you will still not able to upload files bigger than 2MB, because your PHP setting only allow you to upload file smaller than 2MB.
Simply, you can only setup Max Upload (in Edocman) with value smaller than PHP variable: upload_max_filesize
Thanks
Dam