Average count is meaningless except as a comparison between 2 specific burns. The actual number is not critical. Same for total counts, you need to be comparing 2 otherwise identical burns.
The max counts are well documented in the appropriate threads. It mostly depends on your scanning speed and ECC sums, and how well the intended reading drive can correct errors. If you are burning for a picky DVD player, low error rates may be needed. If you are burning for a computer drive, higher rates may be allowed.
There are no absolute rules, except that "lower is better".