If you use soil enrichment on a planet, it gives you another tile to work and increases the planets class. For example, using soil enrichment, you can get earth to class 11. Save, Reload, Earth is now Class 10 again... but the soil enriched tile is still workable. This may just be a display issue... but if you get bonuses for having higher class ratings on a planet (other than the workable tiles) it could be having an effect. As an example, I had a class 6 planet that I was able to Soil Enrich and Habitat improve to class 10 (2 tiles were upgradeable for each .. wheee!) making the planet class 10.. now it is class 6 again and I wonder if I am missing out on any bonuses.
Rob
