I burned serveral Verbatim DVD+R (Printable Surface ReorderNo.43232) 4x at 8x with my Plextor 708A without problems. The Media code was always MMC-002-00.
Now i bought a new Pack of Verbatim 43232 DVD+R and 3 DVD’s failed to read after bruning them at 8x. I checked their Media code and it was MBIGP101-R03-00.
Then i opened some other 10piece boxes and in every box there were 3 of those MBI and 7 of the MMC DVD+.
The bad thing is that my plextor thinks the MBI could also be burned at 8x.
So check the manufacturer id before burning 4x-Verbatim with 8x.