ClamWin AV was updated to 0.97.8 on April 08, 2013. Avast released 8.0.1489 on May 09, 2013. The first Avast detections ever (for me) of ClamWin signatures were in the second week of May, 2013. There have only been 3 of them, with the last one several days ago. Actually, this seems to indicate that Avast scanning is more aggressive.
At any rate, the detections have done no harm as I have Avast set to ask as first option. Avast streaming updates are likely more aggressive than before, as there have been a lot more of them lately.