When I found as much, if not more, than, I had an impression that than might be wrong at first because the phrase looked like a variation of as much as. However, there’re a lot of examples of both of them on the Net. Do they have different meanings?
- as much, if not more, than (Harry Potter and the Order of the Phoenix (5) [US Version]: p501)
He was no longer their sullen host of the summer; now he seemed determined that everyone should enjoy themselves as much, if not more, than they would have done at Hogwarts, and he worked tirelessly in the run-up to Christmas Day, cleaning and decorating with their help, so that by the time they all went to bed on Christmas Eve the house was barely recognizable.
- as much, if not more, as (From Google search)
The imports in 1877 amounted to as much, if not more, as in 1876, though I have not been able to procure the exact figures.