Foreign earned income exclusion

I am having the same issue as a posted question from last year- for the last two years. While my wife’s foreign income qualifies for exclusion, including it in our calculations increases our tax liability significantly. I have spent 2 hours with TT experts and they cannot explain why the software does that. I’m trying to get a call with a CPA to explain. Beyond the mechanics of the software- Can someone explain WHY excluded income does this? There’s no way that excluded income “layered” onto mine would add tens of thousands of addition tax. Or?