My daughter goes to college at the other end of the state. It’s 280 miles of freeway, and I consistently make the trip in less than 4 hours. I can accurately project a time of arrival based upon the conditions for that trip (like whether my wife is coming with me, and what the road conditions are).
I have experienced many situations in which traffic jams, weather, illness, mechanical breakdowns, or not paying attention resulted in the trip taking longer than I expect. My own behaviors have only limited impact on the outcome compared to the effects of these other factors. For example, on one trip, I experienced construction traffic delays which added nearly two hours to the trip, and alternative routing would not have improved the situation. Should I claim a 2 hour savings from this baseline for other trips? Projecting such savings would be stretching credibility - more realistic expectations for average speed, road conditions, and vehicle reliability would be more reasonable.
The specific interventions (clear priorities, automated testing, focused attention) are legitimate improvements that clearly can contribute to improved performance for a team, especially when they are contrasted with the alternative behaviors. But I believe there are several questions to ask about such claims: