By the way, if you look at Vazquez' numbers from age 24 on, his AL/NL splits are as follows:
NL: 3.57 ERA, 1.162 WHIP, 8.5 H/9, 1.1 HR/9, 1.9 BB/9, 8.5 SO/9, 4.4 SO/BB
AL: 4.52 ERA, 1.258 WHIP, 8.9 H/9, 1.2 HR/9, 2.5 BB/9, 8.1 SO/9, 3.29 SO/BB
I'd say that shows a major difference in his ability to pitch in the NL vs. his ability to pitch in the AL. It's not really fair to compare his AL/NL stats when his NL stats include him pitching at ages 21, 22 and 23 and his AL stats all include years in which he was in his prime (age 27, 29, 30 and 31).