PaulS:
How does that differ from getting rid of the loop, and just executing the 1st statement, the 2nd statement, the 3rd statement, and then the 4th statement?
The difference is in the code before and after the switch() which must be executed once per switch case.
Anyway, it's not relevant to the ghosting issue...that's what I would really like to fix, if possible.
EDIT: found the problem.
I just needed to shiftout an empty byte at the end of each iteration
Though I was doing that by turning LOW the digits data pin 