The final CD, page 4, Adjustable Payment (AP) Table;

Interest Only Payments? Yes for your first 120 payments. Optional/Step and Seasonal all reflect NO

Under Monthly Principal and Interest payments-
line 1 First change/Amount- reflects the total P&I payment "at 121st payment"-
line 2 Subsequent changes-No subsequent changes-
line 3 Maximum payment - reflects the total P&I "starting at 121st payment"

It is acceptable to have starting at 121st payment vs an actual date? i.e. 5/22/2034.

I haven't found anything specific on this.

Refer to: H-24(C) Mortgage Loan Transaction Loan Estimate—Interest Only Adjustable Rate Loan Sample

That appears to support the way it was done, thank you!