In perl, what is the difference between $DB::single = 1 and 2?

What is the difference between putting $DB::single=1 and $DB::single=2 in your code? Both seem to have the identical effect of halting execution at the statement following the assignment when I do a 'c' on the perl debugger command line.

perldebug says that a value of 1 is equivalent to having just pressed 's' to get to the next statement, and 2 is the same as 'n', but what difference does it make how you got to the statement?