They don't have that kind of picking style. It should sound more aggressive, the way Jan does it tends to pluck the strings and give additional percussive feel. Hard to tell without pro recorded sound. The tempo and pattern however are nothing out of the ordinary.
Fastest downstrokes that Maiden did, are, AFAIK, riffs in Seventh Son in the solo section. Live '88 is about the tempo of a typical live Creeping Death. Smith did also some fast and relatively complex-patterned with Dickinson.
Murray is great with downstrokes generally, and he did that Seventh Son live parts with ease.