just had another look at the 1871 Census and Edwards age is 26 and Margaret is 29 the down stroke on the 9 is faded
both their ages are consistent in all of the Census,
I would think Edward has added a few years to his age so as to look nearer the age of Margaret, with her being older than him.
don't discard the Census information, it may show as correct when you find their burial details, the age might come true then.