There is no difference ....... except .........

Today I have written the following sentence to mean "The only difference between A and B is “A is more powerful than B”.

There is no difference between A and B except A is more powerful than B.

But someone says that my sentence doesn’t express that meaning. He says that my sentence is wrong.

I need to be confirmed whether my sentence is wrong. Could someone please help me here?

It’s not exactly wrong, but it isn’t very logical either.
What’s the point of saying ‘there’s no difference… except’?
This is a more preferable option:
The only difference between A and B is that A is more powerful.

Hello Ma’am,

Does the following expression sound OK to you?

  • There is no other difference between A and B except A is more powerful than B.

Leave out ‘other’ and it will be fine.

‘There is no difference between A and B except that A is more powerful than B’ would be clearer and convey the same meaning.

No clearer. Not incorrect, but unnecessary.
I would use ‘that’ with
The only difference between A and B is that A is more powerful than B.