Nero 7 speed/confirm OK

I have Nero 7 Smart Start & LG GSA-H62N burner. When I’ve burnt DVDs it says in the log, e.g. sector 13225 has different content to the source, yet it says confirmation O.K.?? on video it’s O.K. but would this be a problem recording say a program? To try & fix this I’ve now tried setting every page where speed is mentioned(even read) to 8x from 16x but it still says burning at 16x?? is there somewhere else to set speed?