How is route automatic metric calculated on Windows 7?

I don't think it's new to Windows 7, I think it's there in Vista too.

However, I don't believe there's been a published set of rules that the algorithm follows, just that it's now on a scale of 1-9999.

I don't know the algorithm as well, but you can force a specific metric by changing it on the TCP/IP properties of your network card. On the General tab, click Advanced, uncheck Automatic Metric and set whatever value you like.

I tried this with somewhat a moderated sucess:

• - On a restart this setting gets overwritten;
• - When I connect my 3G modem it sets every other network adapter to a Metric value of +3k (while it retains a 30 value on its metric... :( )
• - If I try to add a route rule the metric I defined is added to the interface's base metric, instead of being an absolute value. ([ref][1])

Does anyone know hoe to cincurvent any of these problems?