Do you have someone who is checking the final version of the translation?
If you don't mind giving your clients translations with English errors, then in many instances that is what you are doing.
Once in awhile, I will go through some translations rated 100% and correct them. However, unless I am wrong, you leave the choice whether to accept the correction or not to the person who made the original error :)
If it were my company, I would find a way. But, it isn't.