From the same article:

> As always we test across multiple air interfaces (3G, 4G LTE, WiFi), but due to the increased network load we actually find that on a given process technology we see an increase in battery life on faster network connections. The why is quite simple to understand: the faster a page is able to fully render, the quicker all components can drive down to their idle power states.

If you compare the Nexus 4 on 3G (4.18) and the iPhone 5 on 3G (4.55), the scores are actually very close.