I am on a bit of a personal campaign to liberate people from the mistaken assumption that a "balanced" sulfate:chloride ratio must mean 1:1. For almost any style of beer, much more sulfate than chloride is preferable.
Guess it depends on what kind of beer you are trying to brew. For continental lagers a good sulfate:chloride ratio is 0:1. There are, of course, continental lagers brewed with a fair amount of sulfate but you have to be very cautious with sulfate and noble hops. Doesn't take much sulfate to turn their fine bitterness coarse and unpleasant.
I guess my campaign is to liberate people from the misconception that the Cl/SO4 has the significance so many seem to assign to it. That idea apparently derives from a paragraph in the second edition of Handbook of Brewing (ed. Priest and Stewart). This book is definitely British oriented. The actual statement says that "many" authors have referred to the importance of balance. Every single one of those cited in the references is British The single sentence that has resulted in propagation of this idea reads "It appears that, in many cases, it is the relative ratio of the two ions that has the major flavor influence..." It does not say all cases, or most cases, or the majority of cases. In my experience, "many" does not include any case in which noble hops are involved and my reading of the German texts seems to confirm that sulfate = bad where noble hops are involved. I am not an Anglophobe. It's just that brewing practices from the rest of the world (where they make better beer, IMO, but that's just my taste) need to be taken into consideration.
My passionate campaign is to get people who publish spreadsheets to take out anything that calculates an RA "requirement" from beer color. The correlation between the two is just too weak. Judging by the posts I've seen here and on other boards the SRM - RA thing has ruined more potentially good beer than anything else I can think of. This relates to the other problem I have with these spreadsheets - they ignore pH and you can't do water chemistry without dealing with pH unless you skip carbonates and caveat that the spreadsheets pretty much fall apart as pH increases much beyond 8.3. If you throw away the notion that you require an RA of 400 to brew a 40 SRM beer you should not find yourself in the position of having to add carbonates to adjust RA and it is immaterial that they don't do the calculations correctly.
For example, if I tell the EZ spreadsheet that I want to brew a 40 SRM Stout (e.g. Guiness) from DI water it tells me I must add 1.955 grams (yes, grams) of calcium carbonate for each liter of water! That should immediately strike anyone as insane. It goes on to tell me that this will produce an alkalinity of 952, an RA of 402 and be suitable for beers 38 - 43 SRM. But 1955 mg/L CaCO3 increases alkalinity by 1955 ppm as CaCO3 - there's a reason why alkalinity is specified "as CaCO3". IOW EZ accounts for about half the buffering capacity of CaCO3 and thus directs the user to add twice as much as it would take to get to the "required" RA. If a brewer were to follow this advice he would presumably realize that this much chalk (37 grams for 5 gallons) is not going to dissolve and add it to the mash or suspend it in the water and mash with the suspension. The pH of such a mash would be way high. The theory behind these spreadsheets would require the roast barley to contain 714 mEq of acid which would dissolve and neutralizes the CaCO3 and lower the pH to 5.2. Believe me, the amount of acid in a pound of roast barley is nowhere close to 714 mEq. To get to pH 5.2 the brewer would have to add about (the roast barley will supply a little) 57.8 mL of 23 Be' (hardware store strength) hydrochloric acid!. Fix the thing to correctly calculate the alkalinity correctly and the required acid goes down to 356 mEq. Still completely absurd.
So my recommendation would be to take out the "Best for this SRM" thing so brewers are not mislead into thinking they need such high RA (I do very nice dry stouts darker than 40 SRM with water with an RA of about 36 and the pH is still a little higher than I'd like) and then take away the CaCO3 input. There is little reason why a homebrewer should ever be adding chalk to brewing water unless he is trying to match a particular profile. Getting a spreadsheet to the point where it can do that correctly takes it beyond "simple" pretty quickly. Removing the carbonate removes the necessity to fix the chemistry in that department. Without carbonate (bicarbonate can stay) ignoring pH will give a pretty fair approximation as long as the pH is below 8.3. Even at pH 9 the error in assuming that all alkalinity is from bicarbonate is only about 10%. My final recommendation is to leave the Cl/SO4 ratio but take out the "Best for this style" field because, while there may be some validity to those recommendations for ales (the type of beer homebrewers do most frequently) they are not valid for lagers, wits, wheats, lambics, abby beers....
Having simple spreadsheets is a wonderful thing but the chemistry imposes limitations on simplified calculations. If those limits are exceeded then the simplified calculation can lead the user down the garden path. This would be the case with ignoring pH: don't go above 8.4 or so and you're OK. But the simple spreadsheet must also be based on sound fundamentals. The simplified chemistry must be applicable at pH below 8.4 (as it appears to be here except where carbonate is involved). The premises behind the SRM/RA relationship and SO4/Cl balance are seriously flawed.