Absolutely do not want GT-Al to be matched to Xy-Al. The intended rarity of GTs version (its not even a direct ore and must be processed from other things) is in serious conflict with the actual commonality of Xycrafts version.
This is the weakness of dictionary matching of ores, and can already see the issue between GT and RP rubies and emeralds. RP expects, and gives an approprite valie in crafting while GT expects they are far rarer and gives them such value.
Its as if some mod declared something called diamonds to spawn in one of every three blocks in the game, and Forge decided that that stone will be able to make the best tools weapons and armor in game.