Hi Sean, in any case when you add more items in a row, spacing becomes challenging. taking that into account; are more then 6 steps really needed?
Answering your question; this isn't a spacing issue, you didn't add the class "wizerd-step" to the added columns. That class, will take care of proper spacing. See my example
in this example you'll see that I added 2 columns in the front & end. because 12 cannot be divided by 8. Another option is to use an offset or right/left alignment classes.