Generate Rows: increment letters like numbers

Hello everybody!

I'm using the Generate Rows to increment letters like numbers (example: D+1=E).

I used the formula: CharFromInt(CharToInt([Alph increm])+1)

CharToInt([Alph increm])+1) --> Converts the letter into the relative number/code and it adds 1 (Letter A = 65 // 65+1=66)

CharFromInt --> Converts again the number/code+1 into the relative letter (66=B)

And it perfectly works, but it creates 26 rows of uppercase letters (from A to Z) plus 26 rows of lowercase letters (from a to z) and a couple of rows of brakets, underscore, etc....

If I change my Input tool replacing A and Z with a and z lowercase, it returns me only 26 letters.

I know I can just input a-z lowercase and make the whole expression in the generate rows tool uppercase, or I can also input A-Z and then filter with a regex that tests if it's uppercase or not.

But why does the generate row tool act this way?

Why from A to Z means both upper and lowercase letters plus [\]^_` and form a to z only means lowercase letter?

Any idea, explanation?