Comcast Emails Suddenly Reported as Throttled Over The Last 4 Months?

Good Morning, 

Over the last few months, my organization's SMTP server has reported a very large increase in "Throttled" responses (postmaster.comcast.net/smtp-error-codes.php#RL000010), preventing our customers from receiving emails they opted in to, in some cases customers from many years ago. These are heavily curated lists (real-time updates to user preference on email delivery) of recipients who trust us for correspondence on the documents we provide, not spam or unsolicited emails, which our IP address has never sent. the best document we have found regarding the reason for this throttling is below:

https://spa.xfinity.com/postmaster?faq=comcast-mail-errors#RL000010

Which simply states a (to my understanding, contradictory) response to fixing throttling issues:

"

If the rate-limit is impacting your ability to deliver email, shortening your server's delivery retry interval may resolve the issue. Please be mindful that these are reputation-based mechanisms, and there are many factors that can impact those reputations. If the sending entity has poor reputation, sending "faster" or "more", may be increasingly detrimental. Ensure that you've also evaluated engagement, list auditing, and other best practices.

"

So, shortening the retry interval, may help... or make the problem worse, according to Comcast's own policy on throttling. Which is it?

Over the last two months, we've tried testing - on our own behalf, since calls with Comcast haven't been very helpful - different SMTP throughput settings to guess at what Comcast may consider acceptable, with no helpful responses back from Xfinity/Comcast on what exactly is expected from our company to alleviate this issue. We need clarification on exactly what actions we should take for our client's important emails to be delivered successfully. 

Yesterday, I found a post on this forum about this very same issue below:

https://forums.xfinity.com/conversations/email/emails-not-received-to-comcast-addresses-in-mass-distro-list/65b0242c22d9f633de7f5add

It looks as if an employee, XFinityAlex, is able to fix users' throttling issues by having those users DM him their domain or IP address so he can reset their reputation on Comcast/Xfinity's side. Can this be done for our IP address, given that we've had many trouble-free years of sending to the willing recipients of our emails? 

If not, can you please provide to us (and other users) useful rules on how we can successfully transmit our emails again?