When I check the box to say that this was for purchasing a home, the tax estimate does decrease by $1000, but I'm wondering if it should be more.
That implies that you made your first Roth IRA contribution after 2015. In that case, use of the $10,000 for a first-home purchase means that you are not subject to the 10% early-distribution penalty (the $1,000 decrease in your balance due) on the $10,000, but the $10,000 is still subject to ordinary income tax.
