Fixes several more expression issues and cast type check merges.

Server/Items/Container.cs

@@ -1272,7 +1272,7 @@ namespace Server.Items
         {
           Item item = list[i];
 
-          if (type.IsAssignableFrom(item.GetType()))
+          if (type.IsInstanceOfType(item))
           {
             int need = amount - consumed;
             int theirAmount = item.Amount;

Server/Region.cs

@@ -425,7 +425,7 @@ namespace Server
 
       do
       {
-        if (regionType.IsAssignableFrom(r.GetType()))
+        if (regionType.IsInstanceOfType(r))
           return r;
 
         r = r.Parent;