I filled out a 9465 payment plan - but as I was about to finish - TurboTax also requested a 1040-v? Why do I need to fill out a 1040-v?

I've never owed so much that I had to pay in a payment plan . . . I figure my steps are: 1) file and 2) set up a payment plan . . . I did that - but why does it ask for a 1040-v???   Assuming I do things correctly can I still use the IRS web site to manage my payments?