If I qualify for the foreign earned income and exclusion exemption (100% of my income is covered under it) then why does my tax due increase after claiming it?

I made under $15000 and all of it was earned abroad. I qualify for the foreign exemption (all my income). When putting in the 1099-MISC under self-employment income section the tax due is normal. Then when I claim/apply the foreign exemption, the tax due increases a few hundred dollars. Why?