ARR health test issue with URL Test: twice the requests

Hi.

 For the Health Test I only use the URL Test. The interval is 5 seconds. The strange thing is that according to the IIS logs, I have 2 simultaneous requests for each period. I removed the IPs. Can someone explain?

2011-05-24 18:33:33 xx.xx.xx.xx GET /health.html - 80 - yy.yy.yy.yy - 200 0 0 202
2011-05-24 18:33:34 xx.xx.xx.xx GET /health.html - 80 - yy.yy.yy.yy - 200 0 0 218
2011-05-24 18:33:39 xx.xx.xx.xx GET /health.html - 80 - yy.yy.yy.yy - 200 0 0 218
2011-05-24 18:33:39 xx.xx.xx.xx GET /health.html - 80 - yy.yy.yy.yy - 200 0 0 218
2011-05-24 18:33:44 xx.xx.xx.xx GET /health.html - 80 - yy.yy.yy.yy - 200 0 0 234
2011-05-24 18:33:44 xx.xx.xx.xx GET /health.html - 80 - yy.yy.yy.yy - 200 0 0 218
2011-05-24 18:33:49 xx.xx.xx.xx GET /health.html - 80 - yy.yy.yy.yy - 200 0 0 218
2011-05-24 18:33:49 xx.xx.xx.xx GET /health.html - 80 - yy.yy.yy.yy - 200 0 0 202

edit: s/heath/health