diagnostic charges

just wondering what other dealers policies are concerning diagnostic charges.
do you add the time in with the repair?
do you add a job which states "diagnostic charge"?
do you waive the diagnostic charge if the customer repairs the vehicle?
i realize that diagnostic charges depend on the nature of customers concern,but do not want to scare or run off customers.
however the more diagnostic time i can bill the more my techs make(which makes for happier techs) and the more gross profit the company can make.
do you add the time in with the repair?
do you add a job which states "diagnostic charge"?
do you waive the diagnostic charge if the customer repairs the vehicle?
i realize that diagnostic charges depend on the nature of customers concern,but do not want to scare or run off customers.
however the more diagnostic time i can bill the more my techs make(which makes for happier techs) and the more gross profit the company can make.