Huge water pH difference between BF and BRU'n Water

[Matchrocket]

I've been using BRU'n water for a long time, and its always treated my right and been very accurate. I plugged a known beer/water profile with adjustments into Brewers friend, and I get VERY different results.

Grist, # and color's are the same. Starting water profiles (RO) are the same. Volumes are the same. Mash/Gris water ratios are the same.

I have to double the acidulated malt additions in the recipe to get the same ph in brewers friend vs BRU'n Water.

I know BRU'n water is right for this grain bill. What am I missing?

https://www.brewersfriend.com/mash-chemistry-and-brewing-water-calculator/?id=8YPXBYZ

Brewers Friend
Mash pH *: 5.55
Mash Water Report Before Dough-In:
Ca+2 Mg+2 Na+ Cl- SO4-2 HCO3-
34.4 0.0 8.0 35.9 37.8 16.000

BRU'n Water
Mashing Water Profile 56 0 8 53 63 16
Mash Parameters
Batch Volume (gallons) 10.5 Hardness (ppm as CaCO3) 140
Estimated Mash pH 5.44 Alkalinity (ppm as CaCO3) 13