I missed the deadline for the final estimated tax payment for 2018 (I made the others). I'm still working on my Schedule C inputs but in general I know (within a few hundred dollars) what I'll owe. Can I pay the higher amount now to the IRS and possibly get a refund if my final bill is slightly less? I should make the April 15th deadline but I'd like the peace of mind of knowing I'm paid in full before that.
