There may be a simple reason for this - or maybe not! In 1911 the householder filled in the form - this would probably have been the father. Previously the enumerator called and filled in the form - when possibly only the mother was at home. Mother would remember the child's Baptismal name - even if it wasn't used regularly, but father probably just did the job without too much thought.
On the subject of Baptismal names and form filling - the entry in the Parish register was, in many cases "slightly" abridged, I suspect that at the Baptism the priest used the full name given to him at the time by the Godparents - form filling was not a priority, it just had to be done, so "Thos of Thos Smith" was the entry.... and sometimes he would even get the first Thos wrong - it was probably John!
I have enjoyed reading these comments, and given some food for thuoght, brought back memories and even educated. Thankyou all