Yeah, both miracle sword buffs have an extra 40% of your magic adjust added in attack rating. However the Tin Crystal Catalyst evens out the difference in the 1.4 for Crystal Magic Weapon and the 1.8 for the miracle buffs.
Darkmoon Blade gets an extra 0.3 added as you rank up though, making it the strongest buff in the game. I.e. its 2.1 bonus well overtakes the 1.4 on Crystal Magic Weapon even with the Tin Crystal Catalyst being used for a higher adjustment.
"I'd rather betray the world than let the world betray me." -Cao Cao