You're simply not able to buy a second house (for your alt) in the first place - so no chance to lose out on 2 million gil.

The only way of owning more than one house would be work arounds with dummy FCs (considered rather "shady" by most people).

You can obviously give up your mains medium house and then buy that smalle house for your alt, but you cant have more than one house at a time in the first place.