Can I copy copied games from DVD+R to DVD-R on a DVD-R burner?

[jondoe]

I have a DVD+RW burner and have made several copies of my games using Nero. I'm gonna exchange my DVD+RW burner for a DVD-RW burner. Can I make copies of the games I burned before using DVD+R discs to DVD-R or DVD-RW discs? Do DVD-RW burners read DVD+R or DVD+RW discs to burn DVD-R discs? Or will I have to copy from the Original games to DVD-RW discs? I was thinking on buying the Sony DVD+RW & DVD-RW if I can't copy DVD+R games to DVD-R discs.
My second question is: can all PS2 versions read DVD-R and DVD-RW? I've read only version 5-7 read DVD+R and DVD+RW. Is this true?