@Christian_Dahlqvist ,
sorry, my bad. i didn't notice April & Jun.
Thank you so much @dadoonet & @Christian_Dahlqvist
Following script work for me.
if (!doc['QuoteRequestTime'].empty && !doc['QuoteResponseTime'].empty) { return (doc['QuoteResponseTime'].value.millisOfDay/1000 - doc['QuoteRequestTime'].value.millisOfDay/1000) } else { return null; }