KepServerEX Advanced Tag update non zero value from a tag

I have a tag on a Molding press for Cooling Time that counts up and then zeroes out.  I am writing the data to a database using a trigger called New Data Flag.  When the new data flag kicks from 0 to 1 I write the data to the database.  Unfortunately the cooling time tag is at zero when the new data flag changes over.  

So I think I can fix this by creating an advanced tag that will monitor the Cooling Time tag.  I only want the advanced tag to update if the Cooling time tag is not zero.  By doing this I will always end up with the last non zero value from the Cooling Time tag when the New Data Flag changes from 0 to 1.  

My assumption is that a derived tag may work but I am not sure how to setup the expression.  Any help would be appreciated.