email delivery status

I´m very new on PMG and not a most like Linux friend, trying to learn more. I have Mailenable installed and running for at least 10 years. Few months ago I learned about PMG and set it to be inbound mail for security. it works very easily. Recent readings about it said that PMG supports DSN...

Hi folks, we are sending roughly 250K mails per day and experience troubles with getting delivery status. It takes about 20 seconds to receive a delivery status per email. That's pretty long. Is there a way to speed up receiving the email delivery status? Thanks