Sorry for the slow reply aplund - busy days!
I think to answer your last post, it might help for me to give a bit of a background on the BIABacus first...
The BIABacus - A Tiny Bit of Background/History
The BIABacus is an accidental but fortuitous "invention."
Some inventions are simple light bulb moments that solve a problem - no work required. Other inventions are light bulb moments followed by a lot of work. The BIABacus is actually the culmination of many inventions that gradually became a major invention (although this is not widely known currently for a variety of reasons).
There are probably well over a thousand unpublished versions of The BIABacus. In fact, the one you see now is about 9 versions ago. Even the name changed over these versions - the current BIABacus evolved from the very simple and innocent, "The Calculator."
It would be impossible to list all the light bulb moments and all the stages of hard work that formed the current BIABacus but I can list some of the very major ones (and the path wasn't as linear or as simple as I write it below):
- Firstly, we became conscious that there seemed to be something not quite right with existing brewing software. But, we weren't the experts so we spent a few years just even making sure there were problems.
- We reached a stage where we knew that some of the most basic maths of existing software was incorrect.
- We then identified the causes of the incorrect maths (poor terminology and misinterpretation of formulas).
- We then attempted (many, many hours) to help some mainstream software correct their formulas or terminology. Some basic things were corrected however many critical things were not possibly due to the fact that to have them all corrected would require the mainstream software admitting that in prior versions they had things completely wrong. (Personally I think they should have done that.)
- At that stage we had started to develop
Clear Brewing Terminology, another thing that might look simple and obvious but took hundreds of hours of thought.
- We then gave up on mainstream software as it simply took too long for us to explain the faults and teach people how to use it at least somewhat correctly. (Remember this site is really all about education.)
- We then had to improve/develop our "The Calculator." This went through some very fancy incarnations (click a button and units would change from metric to US, import/export recipes etc) but, these advanced functions would work on one person's computer but not another's. (A few years lost there!)
- We then decided to strip it bare; no macros, buttons etc.
- By that point, we had a lot more confidence in questioning the status quo (incorrect formulas etc) and so we knew by then that the most basic fundamental of other brewing software was incorrect - extract efficiency (or EIK - Efficiency into Kettle) is a variable, not a constant.
All the above was done with one goal in mind - accurately and efficiently educate.
This is why when you see The current published version of The BIABacus, you see the Sections A to Z.
You
hopefully won't realise just how many hundreds of hours (probably some thousands) just went into the layout. Try coming up with the terminology, layout, logical structure etc given the cell-size/space constrictions. (That's why the spread-sheet cell-size of The BIABacus is so small - every single field had to be carefully crafted to fit.)
And, that's just what you see. Underneath, hidden, are hundreds of complex formulas that all interact together to bring you what you see on the surface.
The Reasons I Say the Above Before Getting to Your Question is...
1. Other software might "look" more attractive but it's slow to use and actually wrong.
2. At this point in time, I don't think the IT is available to economically turn the BIABacus into "graphic software." (We have attempted this previously but shouldn't have because those who volunteered really had no idea of the complexity of the formulas underneath.)
3. This is a powerful bit of gear!
[center]
Now to Your Question - Finally 
[/center]
1 versus 100: Okay, if you type in 1 on the left of Section C, it won't do anything. Change it to 100 though and it will. From memory, what the hidden formulas underneath are asking is, "If the amounts above add up to 100, then the user is probably talking percentages. If not, they are talking weights."
FGDB and MC: Great question. What we found here are many, many things. I'd love to write an essay on them but I think I've already done one above
. Basically, other software has a drop-down list and every ingredient has it's own FGDB / MC etc. But, that is actually not reality. I'll just skip the fact that some mainstream software has their calcs on those figures wrong and instead jump to the practicalities. Every batch of malt varies on its FGDB and MC. For example Barrett Burston Pale Malt Batch Number x made in September could be 3% different in specs from the November batch. Even if you knew the specs of the batch, how will you know the moisture content by the time it gets to you?
This is a good example of how mainstream software can "un-educate" us. (We actually had drop-downs of malts and hops in earlier incarnations of The BIABacus but discarded them for many reasons.)
To cut a long story short, in real life, you won't get better specs than what the BIABacus auto-estimates. The only time you should use Section Y is if adding a significant percentage of sugar or malt extract to your recipe.
...
That's probably enough (way too much?) from me aplund however, it is great to see you exploring, investigating and questioning.
I'd love to be able to see The BIABacus do lots of fancy stuff (eg click on a section and get really detailed info) but, at the moment it's not possible.
It's nice though (and it is a main aim of The BIABacus) to see you asking questions like the above.
One last thing... a paradox... this site has spent so much time developing this revolutionary "numbers" tool however, a motto of this site is also, "have a healthy disrespect for numbers." (Search my posts for "Number respect and disrespect" and some essay will come up
)
PP
For sure could see the difficulty of brewing out of an RV. 
) and we need to get a corrected version out. The formula for WYWU is actually reversed. So instead of dividing x by y it is doing the opposite 
.
