You're right....I just quickly read the Chapter B rule when responding and forgot to recheck the other HASL rule on exchange. Reset to normal.....nothing to see here..Hi Sarge--this does not make any sense at all. If you can buy FBs for 8 and use them as Tunnels instead, what is the point of purchasing a Tunnel? There is no limit to # of FBs you can purchase. You might as well say that Tunnels/Fortified Buildings cost 8 FPP......we have not been playing it this way in our CG. Also, in other CGs exchange of FBs for Tunnels is NA.