Allow "Downgrade after end of term" for recurring/subscription plan downgrades

When I set up a recurring/subscription plan and add downgrade options that are other recurring/subscription plans, the "Downgrade to other plan after current plan expiration ( After End Of Term)" option is not available.

Because a subscription has a billing cycle (for example, monthly), it should be possible to allow members to retain their access until the end of the current billing cycle.

For example, if I pay for a month of Netflix, but I cancel my subscription before the end of the month, I can still watch movies on Netflix until the end of the month.

If one of my users pays for a higher monthly tier, I want them to retain access for the month they paid for, even if they choose to downgrade sometime within that month. After all, they paid for it.