Same output
Have you used a number > 10 .. maybe 100 or so?
Do you use the exact same "wallet" as you used when you created your account?
maybe also try a second optional parameter like 2000
The hosted wallet does not recover numbered account in the same way as the desktop wallet. Even though the hosted wallet uses a sequence it is not the same hash. This is really only because the c++ code is amazingly complex in the way that was done (well easy to do in c++ but not so easy to re-create or debug). I got close but never got it right. We finally just moved on based on good advice and the idea that this was all gonig to be re-written (graphene, yea!!). So, I just used some more of Nathan's great ideas and added a simple hash and the counter. The hosted wallet differs a bit, there is no large number involved your really not scanning much. It just counts and checks every step of the way. You really can't skip numbers. It is straight forward so there is no number exposed in the API, it is done behind the scenes.
There is a Wallet Advance feature where you can try to recover an account by its name. This is a light-wallet account or, for a 'very' short period of time, the hosted wallet used the account name in that hash I mentioned above. In any case, you may gain insight by using it. If you try to recover an account by name that was not created with your recover key you will see something like this 'can't recover, this account is not owned by this wallet'... So, this would confirm you need to check the recover key.