Good morning Ron,
Thank you for your detailed update, this will be very useful for the engineers and perhaps to other customers who are also having the same experience. I'm sending your update over to engineering now. I'll keep you posted on any news.
Just letting you know that I got confirmation from engineering that they've rolled out the same optimization to all customers to improve iMessage/iCloud performance. Your feedback helped push this along and help others! I hope iMessage is still working well for you! Let me know how it's going.
Please don't hesitate to come by the community again if you have any other concerns.