Alerts - Percentage change display incorrect

In the following alerts, which is set up from >10% change in revenue, the alert fires correctly (revenue change is >10%) but the displayed change in revenue is incorrect. Actual is 13%, but alert show 3.99% for Google. Similar for MSN:

TSA Alert: 1-800-Flowers: Change in Revenue > 10%

Name: Change in Revenue > 10%

Alert Created: 01/17/11

Comparison dates:

Compare 01/16/11 with 01/09/11

If revenue yesterday is less than or equal to 90% of revenue same day prior week and revenue yesterday is not 0 and revenue yesterday is greater than or equal to 10 - HIGH ALERT

Assignments that triggered Alert:

Google AdWords:

1. Account: 1-800-Flowers

Distribution: Google AdWords

01/16/11 revenue=66298.54

01/09/11 revenue=76729.75

01/16/11 % revenue Change = -3.9941555336170804%revenue Change = -3.99%

01/16/11 revenue Difference = -66298.5400000001revenue Difference = -66298.54

01/16/11 revenue Difference = -66288.5400000001revenue Difference = -66288.54

MSN/Bing Paid Search:

1. Account: 1-800-Flowers

Distribution: MSN/Bing Paid Search

01/16/11 revenue=13036.57

01/09/11 revenue=14818.38

01/16/11 % revenue Change = -2.24924871829594%revenue Change = -2.25%

01/16/11 revenue Difference = -13036.57revenue Difference = -13036.57

01/16/11 revenue Difference = -13026.57revenue Difference = -13026.57