It's great that your acquisition cost is low. That doesn't mean it's insane that someone else is tolerating a $600 cost per T65 sale when the immediate revenue is at least $600. He's cash flow positive from the start.
$600 acquisition costs would be insane. It's basically the entire first year commission.
$641-600 =$41.00 net
$41+321 =$362.00 (22 month cash flow for Mar25 T65)
$641-200=$441.00 net
$441+321=$762.00 (22 month cash flow)
Not to mention that the MA T65 comp rules mean you're paid the full 2x comp regardless of the time of the year. I'll write $500 December T65s all day long if given the opportunity. I'll make $600 on Dec 1 and renewals start Jan 1.
I see the problem… you don't know what acquisition cost are? If your acquisition costs for a $641 sale is $600, then you don't "make" $641, you make $41.
But you are right that you should be willing to pay more for a Dec T65 than other months. Not $600 though. It's AEP. Basically any sell would net you the same 13 month cash flow.