WTH Why is it not possible to add a second HA instance to Nabu Casa Cloud

I think this is in the gray area of “Month of WTH”, but why is it not possible to add a second HA instance to your own Nabu Casa account?
For a small (only server cost covering) extra amount, this would surely be convenient for many users. But another US$7.74/month just to maintain my mother’s HA instance, for example, is way to expensive for me (especially in these challenging times).

I, personally, would be willing to pay for another full amount for a second (or more) HA instance added to my account but having them together would be useful.
Use case for me is similar to @nicohirsch where I created a ‘security’ system using HA for my parent’s house. They pay for it but it would have been nice to have the option to add to my NabuCasa account if I start to pay it for them.

I’ve also see people mention that they have a cabin/shed/RV/business/etc a second location they run a HA instance in that would be nice to have in the same Nabu Casa account.