I had anticipated both questions SS and they are valid.
No, I didn't prepare 8 serves with linear scaling as it is too much food to waste in the likely event that all information I have been given is correct. Let's just say then that linear scaling is not necessary and therefore wasteful, (also undesirable for my purpose).
There were 3 testers and there can be no more as the comparison sample is gone. As the cook and being more tolerant of spice, my own judgement may be questioned. Both my wife and son agreed they were the same dish with no discernible difference.
Also keep in mind that I deliberately reduced the spice in the X8 serve dish even further than the X 1.5 conversion factor calculated amount. Probably down to as little as 1.3 - 1.4. This would suggest that the spice levels are easily matched in larger cooking preparations by using considerably less than linear scaling. Are the dishes "exactly" the same? Probably not!. Is it acceptable and very close? Definitely!.
You might repeat this experiment and draw a different conclusion. However, for my needs and purposes, this test has convinced me that I will not be using linear scaling when I bulk cook soon to feed 40 - 50 people curries that need to be mild.
Some people really enjoy spicy heat and willingly use extra hot chilli. For such people linear scaling is most likely quite acceptable, even desirable. I on the other hand, enjoy some spiciness in food but find the extreme heat of chilli overload to be ruinous of otherwise enjoyable food. I don't enjoy the burning sensations and I don't need perspiration dripping from my brow to assure me I'm eating nice food.
I will again reinforce the reason I have performed this test. I need to do bulk preparation of mild curry dishes for a target consumer group. This is a very specific test and inquiry for that purpose. It is not intended to be the be all and end all of this discussion.
I do have 1.5 kg of Chicken Breast remaining. This would be sufficient to do another test comparing a single serve to a batch of 4 - 5 serves using linear scaling. I'll put it in the freezer as I won't have time over the weekend. I still have to finish the Andy2295 Base Gravy.