Brian:

Don't know why your client struggled, it's not like you have to pick the correct period with every data entry step.

Though 13 x 4 weeks is the correct option, most of my Restaurant / Hospitality / Retail clients use 12 periods of 4 weeks/4 weeks/5 weeks and repeat. Not sure why.
_________________________
Douglas Dickie
AccSys Solutions Inc
Phone: 1.888.534.4344
ddickie@accsyssolutions.com