Warrior General Games

I have a few questions on the upgrading of Advanced Equipment
1) At what levels can you upgrade advanced equipment?
2) Does the price go up the more you upgrade it?
3) Does "better" equipment cost more to upgrade?

1) http://www.glbwiki.com/index.php?title=Advanced_Equipment
2) Yes
3) No, but it does cost more to purchase from the store.