Why was seulement rejected ?

Question

For a change of pace I decided to use seulement instead of ne...que for the following sentence:

"J'ai eu deux chats." . Write "I had only two cats.": ________ deux chats. My answer J'ai au seulement deux chats... was marked wrong! I understand Chris' response to another use that the focus of the exercise in ne que..but in many of the tests (choose ALL the correct answers) they had both the 'seulement' version and the 'ne que' version as GOOD answers.
Unless my answer has an error which I am overlooking ,or there is a point of grammar why seulement is unacceptable here, I would like to suggest a revision of the test marking to accept seulement.
There may be sound reason why learning to use seulement is beneficial, even if 'ne que' is considered better in formal writing. Based on further reading, I have found that SEULEMENT ALSO can VARY IN PLACEMENT ..to differently focus the restriction. Rules for seulement: Cannot be placed BEFORE the conjugated auxiliary/ does not have to be placed (unlike many adverbs) IMMEDIEATELY after the conjugated verb/can be placed just like the 'que' before the 'target word ' being restricted.
So it seems : I had ONLY two cats= je n'ai eu que deux chats OR J'ai eu seulement deux chats.

I ONLY had two cats == Je n'ai qu'eu deux chats or J'ai seulement eu deux chats.
As usual I stand ready to be corrected!

Accepted Answer

Hi Jameson,     
To say -   
J'ai eu seulement deux chats 
or
J'ai seulement eu deux chats
is not incorrect just not what we are looking for in that lesson as we are testing the restritive ne ...que.
In a freeform exercise it would be accepted just not here.
The reason why we insist on it and I know this from experience, students struggle to use the restritive ne ...que as it is so much easier to say the one-word  'seulement', however, the majority of French people will use ne...que and that is why you need to at least try to use it in a lesson like this to be able to recognize it when spoken.
Don't you agree?

Answer

Hi Jameson,"j'ai eu deux chats"   The requirement is to express "I had only two cats"Obviously, context is always vital to fully understand what is meant.Is this restriction "global" in that the ownership of cats was exclusive of any other animals at all?or "restricted" historically two cats were owned but there were other species owned as well?In this "restricted" context it should be acceptable to write "J'ai seulement eu deux chats"to make it clear that only two of that species were owned; the other species owned were not cats.Perhaps this "global" versus "restricted" point is the reason why your proposal was not accepted?Jim

Answer

" My answer J'ai AU seulement deux chats... "Through the latter part of the question you correctly type "j'ai eu", but in this line you have a typo, which could be significant if written as such in your actual answer.