I haven't been figuring wipes into our savings because moms with disposables use disposable wipes as well. However, I'm now officially adjusting the savings to $20 a week based on a friend's disposable diaper purchases. Her child is close in age and size to Joanna so I'm using them as a control. (Wow, my mom would be so proud that I'm using a Science term!) They go through about 1 big pack a week so if they purchased their diapers without coupons, they spend $20 a week.
So with 4 weeks in CD at $20 savings each week, we add $80 to our savings and return on investment:
Total Personal Investment: $190
Savings To Date: $314
Return On Investment: + $124
On a money saving note, we're still saving money each week even with using formula. Without CDing, it would be more difficult to afford quality formula for Joanna. Thanks to our CD savings and coupons from dear friends, we're only spending $15 a week on formula.