They are the same mid code, but apparently not the same batch. If you want more information about them you can look at the virtually invisible numbers on the inner ring of the dvds themselves. The guys in the Blank Media forum may be able to tell you which factories they came from....but that is esoteric information that won't help you in any way on playback.
Riteks vary in quality. That is just a fact.
If you want more consistent results with DL media switch to Verbatim brand, and if you buy them in local stores, try to get the ones made in Singapore. They can be found at Best Buy and Office Max locally. Online you can order from lots of places, like rima.com and supermediastore.com, but it isn't possible to choose country of origin buying online.