Trying to understand Muse protocol

I bought Muse 1 back 2015 and I’ve been using it until now. Back in the day i tried to do a little research but there wasn’t much information yet but I ended forfeiting. After so many years, my muse is so worn out that it can function properly and I was looking to upgrade to Muse S. I wanted to check if the sensor where the same to my surprise to see that the sensors where in places different than I originally thought

I always thought that the frontal sensors where in FP1 and FP2 and the ear ones, where in T3 and T4

But the reality is that they are using AF7/AF8 a little to the sides and TP9/TP10 way down the bottom.

I always thought that they where using the classic focus protocol FP1-T3 and the classic meditation balance protocol FP2-T4, super popular in ADD treatment.

But for some reason now I discover that the sensors are in modified positions. It doesn’t make much sense for me, because the Muse S band goes around the head, so from what I see TP9 cannot be reached from there, so it’s very confusing for me.

Also another thing that disturbs me a lot, are the protocols using CZ and FPz for reference, instead of an earlobe. Why FPz could be relevant at all? I assume that if you close the eyes FPz is constant but not enough reliable from my point of view. I’ve seen some studies using FPz for ground and mastoids for reference. For solely FPz for reference? I know that there are a couple products that use FPz but I don’t feel this enough reliable

Overall I don’t understand anything. Maybe given that it’s a consumer’s products, they cope with what they have and their limitations? (AKA closing eyes for constant FPz + auditive feedback instead of visual feedback)
Also, why do you think they have chosen an AF7-TP9 protocol when they could have easily aimed with a band for the more reliable FP1-T3?

I would like to hear some insights from you.

PS: In the Othmer protocol, they use FPz as ground, not reference, but given that GND is used as reference in most old NFP hardware, I must assume that for some reason, both Cz and FPz have normative values both open and closed eyes I would not definitely agree according to my measures since they are not constant enough to be considered as good ground as other sites like mastoids or ear lobes.