WebPageTraceListener in ARS 6.5 WI web.config

I've added some custom ASP.NET pages to WI and the pages use our own trace listener. But when I try to write anything to the trace, the folowing error occurs:

An error occurred during the last operation. 
Error:  Couldn't find type for class System.Web.WebPageTraceListener. 
Object:  CN=dummy,CN=container,DC=mydomain,DC=test

I take a look at web.config and find the following:

<add name="WebPageTraceListener" type="System.Web.WebPageTraceListener"/>

If I change it to fully qualified name (just copy from 6.1 :P) the error is gone.

<add name="WebPageTraceListener" type="System.Web.WebPageTraceListener, System.Web, Version=2.0.3600.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"/>

Any concern if I update it this way?
I'm using version 6.5 WI.

Thanks,
Neil