Yes Eros/B4U are separately authored DVD by some other company than DEI (media dimensions, dot media and others) - and are not the same quality. Check this thread over on the old forums to see the difference;
http://www.zulm.net/forum/showthread.php?threadid=282
Also this thread;
http://www.zulm.net/forum/showthread.php?threadid=398
..to confuse matters sometimes the Eros/B4U cases contained the DEI authored disc or the disc replicated from the DEI version with different DVD design. I have Deewaar and Ghatak on Eros/B4U label which are DEI authored discs ???
Ali