Remember that dynos are an inexact science, guys. An error margin of +/- 10hp on a dyno based on (a) dyno type, (b) gearing, (c) ambient temperature, and (d) engine temperature is pretty common.
I could take a car, put it on one dyno, and have it make 160hp. I could then take that exact same car, and by conducting the test slightly differently, have it make only 150hp.
Don't take dyno numbers from various sources at face value. We can say a 99+ 3.8 makes about 150hp stock. Trying to be any more precise than that isn't going to work.