Hi again
Thanks for the post, KB, but I do think you are misunderstanding me.
I do realise that there is going to be day-to-day and batch-to-batch variability that will never be perfectly predicted with any program. What my post is about is due to what I will explain below.
My understanding of the purpose of BS2 is two major functions:
1) Simplifying recipe formulation
2) Recording brew session data - particularly as one of major mantras in homebrewing is to take lots of notes
Using the information from 2 means that the predictions from 1 will be improved. So called "dialling in" of any system.
My point is that, while BS2 is good at point 1, it has some parts missing to achieve objective 2. Thus, there is also some deficiency in step 1. Further, without more accurate info from objective 2, the assumptions for step 1 then become little more than educated guesses.
No matter at what step extract or volume is lost, including grain absorption, the more information that you have from previous sessions, the more powerful your prediction for future sessions will be. It also allows a brewer to identify where problems are more accurately. For example, my question about differing gravities (that you - KB - and Oginme were helping me with), didn't seem to have an easy solution, but with more information, I hope to eventually be able to find the problem.
Of course, with the 'Calc Boil Vol' ticked, it also automatically updates all the fields, including mash and sparge water, which means that, once a session is underway, this needs to be unticked to be able to keep your data accurate (eg if you change the trub as to that observed, BS2 changes the mash and sparge water volumes retrospectively, making the brew session data inaccurate).
All I was asking for was fields that allow measurements to be recorded at each stage of the process, then a way to easily compare predicted and actual values. The fields that I was referring to were just some of the fields that I thought would be recordable. Indeed, with the addition of the sessions tab, Brad went some way to including more of these fields for this purpose already.
Thanks again