Without Estimated ACWP, timing mismatches between ACWP and Budgeted Cost for Work Performed (BCWP) cause false cost variances to appear in the Integrated Program Management Data Analysis Report (IPMDAR) information reported to the customer. Typically these variances are favorable and can mask other unfavorable variances. Additionally, if these variances exceed reporting thresholds, the explanations clutter Format 5 of the IPMDAR with variance explanations that discuss timing problems of the accounting system rather than actual performance issues.