This is the problem with old CE clients, they use different initialisation vectors and rules for passphrase truncation so can come up with different HEX keys vs the IV being used on the router, that and passphrase length impacts key output.
Use a
5 digit passphrase to generate a WEP64 key and a 13 digit one for a 128 key.
For example. If I use 12345 as the passphrase here:
https://www.wepkey.com/
http://network-logix.net/
https://www.speedguide.net/wlan_key.php
You will get 3 different HEX keys
1234567890123 will generate a 128 key, not a 64 as it is 13 characters long.