IBAN Key Calculation modulo 97

Thank you very much for your valuable help. Super cool!
Have a nice day

euh .. well, when trying to use it, I'm having issues .. when I want to apply it with a French RIB (whether it's lettered or not in the account number), it seems unable to calculate the key => so I get the message #NUMBER!
Do you think you can do something ...
Thank you very much for your help.

The formula I asked the developers to apply in its literal form
is :- If the payment country is France, the IBAN and BIC fields must be consistent.
* The RIB is structured as follows:
bank code = 5 BBBBB
branch code = 5 AAAAA
account number = 11 CCCCCCCCCCC
rib key = 2 KK

* The IBAN consists of the RIB data (27 characters)
FRXXBBBBBAAAAACCCCCCCCCCCKK

The first two characters are: FR (ISO2 code for France)
The 3rd and 4th characters are: XX (IBAN key)
From 5 to 9: BBBBB (bank code)
From 10 to 14: AAAAA (branch code)
From 15 to 25: CCCCCCCCCCC (account number)
The 26th and 27th are KK (rib key)

If both RIB and IBAN are provided, they must match => the payment type is transfer

- If the payment country is France, the IBAN key must be calculated according to the algorithm:
1- IBAN code place 00 in the IBAN key field FR00BBBBBAAAAACCCCCCCCCCCKK
2- place the first 4 characters at the end of the code BBBBBAAAAACCCCCCCCCCCKKFR00
3- replace letters with their corresponding numbers (A=10, B=11, C=12... Z=35) and thus BBBBBAAAAACCCCCCCCCCCKK152700 (F=15 and R=27)
All letters must be replaced
4- Perform the modulo 97 command on the obtained result
Mod97 = BBBBBAAAAACCCCCCCCCCCKK152700 MODULO 97
5- perform the subtraction 98- Mod97 = IBAN key (XX)
6- the resulting IBAN code is therefore: FRXXBBBBBAAAAACCCCCCCCCCCKK