Jonathan Chait takes apart the idea that evangelical Christians are more likely to be opposed to government budget deficits than other Americans; as Chait points out, spending and deficits are two different things, and one can be in favor of somewhat lower spending and still support overall policies that would yield larger government budget deficits.
What I suspect the polling shows, rather than anything particular about evangelical Christians, is the success of the GOP war on budgeting. Once fiscal conservativism, and even "balanced" budgets, are defined not as having government revenues equal spending but as not spending government money on things that the government (in one's opinion) should not be doing, then the conservative position makes sense. At least, in those terms. And evangelicals here are, near as I can tell, working within that conservative frame.
Of course, once you so define fiscal conservatism, you leave it open to actual massive budget deficits. But I suspect all we're seeing here is some Christian conservatives using religious or semi-religious language for policies well within the GOP mainstream, and defined by that mainstream.
At any rate -- nice catch!