I suspect the math is right but the writer doesn't understand the difference. 150k credit + the standard 35% rate on 1m cost would be 500k net. But this only

I suspect the math is right but the writer doesn't understand the difference. 150k credit + the standard 35% rate on 1m cost would be 500k net. But this only actually works if you would have had to pay 500k in taxes to begin with. If you're losing money or doing other tax avoidance stuff, you don't actually get the full benefit.