Quantized/predictable settlement

When companies/people pay bills, they often want to pay on a regular interval at specific times (for tax & accounting reasons). Automatic payments are fine, but it's still best if they happen at regular intervals.

Unfortunately, in the payments contract, any party can call "settle" at any time.

Idea: Make it possible for some party (e.g., the client?) to specify when a rail can be settled. Ideally this would be a calendar date, but that can get complicated. Maybe this is better specified as a minimum settlement interval?

This requires product input from someone who understands this stuff.