DAX formula to convert time HH:MM:SS into decimal time mm.ss

[IwannaBeLikeU]

Call center data - due to the number of records, I'm importing call data into Access and setting the time field type to "date with time" and displaying hh:mm:ss. When I import this data into PowerPivot for Excel consumption, I create a pivot table and try to average the time data, but I get an error message due to the type of data. So now I'm thinking I'll convert the HH:MM:SS to seconds, but I'm having an issue with the DAX formula.
"=HOUR('Contact_History 18'[Handle Time])*3600+minute('Contact_History 18'[Handle Time]*60)+Second('Contact_History 18'[Handle Time])"

For 00:08:10 I get a result of 20.00 (That should say 490 seconds)

Any help on this matter would be greatly appreciated.

 

[IwannaBeLikeU]

Whole Number - General. I didn't set that. In fact it's Auto (Whole Number).

I can't believe all this hassle for a typo. "e])*3600+minute('Contact_History 18'[Handle Time]*60)+Second('Con."

I would have been working on this for days without your help. Thank you so much.