Pro rated refund on the quarterly is handled quite differently, as you're saving 20% which I'm able to do hoping you'll keep it the entire time
What happens is there is a pro-rated for the rest of the time remaining minus a 25% fee.
Quarterly payments with the 20% discount was designed for either those needing to save money, or a thank you to customers who trust in us
Ads and donations are totally up to you, it's your server
Billing normally starts on the day you order the server. Order it on the 20th, you'll pay on the 20th of each month unless it's quarterly in which you'll pay on the 20th of every 3 months.