It doesn't matter if you have twice the total amount of salts, if you likewise have twice the amount of water. Concentration is what matters.
Anyway, in my opinion, salts are overrated anyway, since malt itself contains like 90% of the salt you will end up with in the finished beer anyway. Any other additions are just extra. When I think I can get away with it, as long as my mash pH is where I want it, I just use tap water or a blend of tap and distilled, and try not to use extra salts at all anymore.