Yes. You should go for revaluation.
I got 5.5 in writing, I had applied for revaluation and score increased by 1, and finally I got new IELTS marksheet with 6.5 in writing.
Only thing is that revaluation will take 2 months and cost 8k (in Gujarat, not sure about other state/country). If any changes in score then 8k will be refunded.