My DS is almost 7 and is doing 3rd grade math - he needs to do 3-4 pages of math homework every weekday with a mix of computations and word problems. He is a very fast worker. In the first 2 weeks, the homework took as long as 30 minutes only for math (excluding the LA and the weekly test reviews) which was surprising to us because we are used to him finishing the work in 5 minutes in previous years. I had to sit next to him to talk him through the process. But, in the last week or so, he is doing it in under 15 minutes, accurately and completely on his own.
So, I suggest that you wait a couple of weeks to see if things improve - it could just be that he is taking a longer time adjusting to the requirements of acceleration. And as for the word problems, ask him to slow down, pick out the "key words" in the problem and circle them first and then solve them. This is what I tell my DS to do - and it has improved the accuracy.
