HP41 Fullnut - Halfnut, different shift functions for Alpha

[Papymouzot]

Hello,

I just noticed something which looks strange to me...

Look at the photo, three 41CX

left 2329S fullnut (white)
middle 2426S fullnut the Alpha shift functions are different (orange)
right 2640S halfnut, we are back to the 1983 keyboard layout (white)



two CV
left 2545S halfnut orange Alpha shift layout
right 2636S halfnut orange Alpha shift layout



two C

left 2020A fullnut (of course) orange Alpha shift layout
right 2153S fullnut orange alpha shift layout



if I recap by date I have

1980 orange
1981 orange
1983 white
1984 orange
1984 orange
1986 white

What was the reason for these different Alpha shift functions layouts ?

They seem inconsistent when looking to the serial numbers / dates ... why ?