You need to remember that the age as given in the 1841 census is rounded down to the nearest multiple of 5 for those over the age of 15years. (And sometimes younger than that, seemingly depending on the enumerator.)
If the guesstimated age in 1841 says 40, then they could be 41, 42, 43, or 44. Sometimes the gap is larger, because the enumerator chose to literally go to the nearest 5, so an age of 45 could be 45, 46, 47,48, 49, 50, 51, 52, 53, or 54..
1841 really was hit or miss, and sometimes the age ten years later (and so on) was given to match the previous age, because who wants to upset the government?!
Then there are those who get progressively younger every ten years - and randomly older.
Any given age from a census should be taken with a very large grain of salt, and balanced against what is given on other documents, if any.