Modern SD ammo is better because it is a more consistent expanding HP, even under adverse conditions....like wind shields, etc.
Older style UMC HP's will perform consistently, as designed, only under ideal near picture perfect situations.
And we all realize that is not going to happen in the real world.
IMHO, there is no logical reason not to be using ammo from "the list"..... none of us use 1990 tech computers ( UMC JHP )...
You could even compare this to '60's and '70s muscle cars... modern muscle cars have everything the 60's muscles cars had as well as modern AC, Fuel injection, decent MPG, better handling....
$15 / 25 rounds is what you can buy ammo from the list for. Granted in 50rd boxes.. but...