Counting the children of William Fage: mysteries of the 1911 census

My great-grandparents William John Fage and Alice (nee Cade) appear in the 1911 census at London Road, Sandy, Bedfordshire. William is aged 39, born in Sandy, and a Market Gardener's Labourer (as he seems to have been all his life), Alice is 38 and born in Gamlingay, Cambs. They have not completed the 'years married' column on the census return (although I know from their marriage certificate that they married in 1893). The 'total children born alive' entry is 6, but there are no other indications re: children still alive, nor children who have died. And this is where the mystery comes in.

My knowledge of their children is based largely on three sources so far: my mother's memory of her own mother's family; the 1901 census, pages from a family bible and a newspaper account of William's death and funeral in 1940.

Listed in the 1911 census return are:

1. Albert Victor Fage , 13 (born 1898)
2. Jesse William Fage, 12 (born 1899)
3. Elizabeth Sarah Fage , 9 (my grandmother, born 1901)
4. Jim Fage, 6 (born 1905)
5. Susan Elizabeth Fage, 5 (born 1906)
6. Aannie Vere (sic) Fage, 6 months (born 1910)

Previously I had thought that their children were:

1. Frederick John Fage, born 1896 (confirmed in the 1901 census, family bible and 1940 newspaper article, married to May)
2. Albert Victor Fage, born 1897 (1901 census, family bible, POW article in local newspaper, medal roll index and 1940 newspaper; married Mary Louisa Cade)
3. Jesse William Fage, born 1899 (1901 census and certificates from a MyRoots contact)
4. Elizabeth Sarah Fage, born 1901 (birth, marriage and death certificates)
5. Violet Fage, born around 1904 (known as Dot; family stories only, said to have married Frederick Francis)
6. Susan Fage, born around 1906 (family bible, 1940 newspaper, said to have married Billy Plumley)
7. Vera Fage, born around 1910 (1940 newspaper and family stories, married Eric Whiteman)

Frederick would have been old enough in 1911 to have left home. But I didn't have any record of Jim Fage, born around 1905, so must look at BMD records for him.

And what about Violet Fage? I can't find her elsewhere in the 1911 census (I thought she might have been called Dorothy, given her nickname, and there is an eight-year old Dorothy Fage living with grandfather Harry Jarvis. But she is the daughter of Elijah Jesse Fage, William Fage's brother.

And was Vera christened Annie? Again, BMD researches are needed for all these children. 

And more to the point, why did William say that total number of children from the marriage by 1911 was only 6? There are six at home at the time, so perhaps that's how he interpreted the question. 

As usual, finding some answers only raises more questions!