It's not really about ballistics, twist or throat to them, it's about contractual obligations.
If you want to manufacture anything, you have to estimate demand and order at least a year in advance from your suppliers. A barrel maker won't gear up to deliver several thousand barrels to your door without iron-clad contracts in place. There may be an option for changes, but the added cost for that will be specified in the contract as well.
So a major issue at play is that LAW likely already bought and committed to buying and ordered barrels in the various twists they originally thought the market would want based on what other manufacturers are currently offering.
If they change specs mid-stream what would they do with all the unwanted barrels?
Changes in twist on unbuilt barrels would cost zero and should be written as such. I'd have reservations about any company that would sign a contract where they're charged for changes to something that's not even built yet and doesn't impact the barrel maker's COGS. They're not sitting on a years worth of barrels in the shop right now.
As to the 1-9 flinging 105's - the runt's Ruger groups 105 Amax's rather nicely here at 580 feet ASL.
