It would be cool if there were a triggering event for options. I'm looking for the options of paying in full or a payment plan. If the customer pays in full, easy peasy. If they want to break payments out over time then a different plan is shown that incorporates appropriate amounts.

Yes! Would also love the option to let them select between which payment plan they want & allow it to automatically calculate at checkout

Yes, the common practice is 50% upfront and 50% at mid-milestone or something for a project.

But we can be creative and offer multiple payment options to incentivize full payment up front with a small discount, and of course longer payment terms with a small price increase.

Just like the table below.

Yes, I need this too!

In my proposals I offer 3 options, ranging from a lower priced single item to a high-ticket 6-month package. It doesn't look good, nor does it make sense to the client that they all are on a payment plan.

For now, I have text at the bottom saying that they can email me if they want the option to do a sgl payment. That way I can create an invoice. So, it works, but it creates more work.... I can't automate this, because each of the 3 items have optional add-ons (because who of us doesn't like the idea of upselling so we can get more cash in the bank :)