Hi,
I'm wondering why you are using the current tier system instead of a "pay per m²" system. I think a lot of people want to have more land, yet they don't want to tier up, because they can't afford THAT much land in order to completely fill their tier. People don't want to pay for something that they dont possess.
Example: I'm currently holding 2560 m² and I would need about 6k m² for a project. Still I would have to pay the 8k tier. For maximum efficiency I would have to buy 2048 m² more, but I cant afford that. That's why I'm not going to tier up.
Seeing that example you can see that you are indeed losing money. The tiers don't fit the individual needs.