ok the 80%.... is like 40% of what the house will resell for so its actually bad.... and yes I speak from experience here

bought my private goblet large at 40 mill then let it relinquish so I could buy a fc house. after 45 days it relinquished at just over 30mill and the initial price same plot was 72 mill....

So its actually a silly system may as well give 100% back as you wont be able to buy that same house with 20% more....

on a side note large at 200 item cap was always half empty but managed to get a lavender med though I wanted a mist med but they go so fast....