Yes, imagine where it would be now 25 years later. I should have gone higher

I recommend not placing on ground or gravel. Concrete blocks is a better choice. My blocks have sunk 4 inches, and runners now in contact, you don't want that.

If you live in a termite region treat the area just before delivery, you'll never have better access. Termites can bridge over pressure treaded runners and get access to untreated areas.