The failure-to-file penalty starts the day after the extended due date (usually October 16th).  But the failure-to-file penalty is based on the unpaid amount as of the PAYMENT due date (April 15th).

In other words, the failure-to-file penalty is based on the unpaid $200,000 that was due by April 15th.

Plus of course the failure-to-pay penalty and interest also applies.