DFVCP penalty for late filing is $10/day late up to $2,000 for a large plan. Filing on 10/18 (today) would be 79 days late for a fee of $790. The full $2,000 would not be hit until mid-February.
Note, that is the DFVCP penalty for fessing up your lateness. If the DoL and/or IRS get to you first, it's the $25 and $1,100 a day fine.