Yeah, I thought NA should've only been around #150. But I could see that last digit wasn't a zero.
It's not the first to be counted twice. It happened with Tales of Suspense too, counted towards both Captain America (which originally replaced TOS at issue 100 in 1968) and the Bucky and Hawkeye mini (which had the Legacy number of 100).
That legacy number should really be either four less (if you don't count No Surrender) or twelve more. U.S.Avengers should count, as it was a continuation of Ewing's New Avengers. Doesn't make sense to count Ewing's New Avengers and No Surrender, but not the dozen issues in between.