That could be the start of an interesting discussion. The way some company's rules are written, you don't have a choice about whether or not to have an engineer. The engineer may have little real understanding of scaffolding beyond reading TG20 so does that trump the extensive practical and theoretical training that a scaffolder has undertaken? I'm not sure that it always does.
I would suggest that if the engineer has drawn something that doesn't look right or goes against the scaffolder's training and experience, it should be raised with him as a discussion point rather than a request for approval - in my experience some/many/most (delete as applicable) engineers can be stubborn and dogmatic on occasions and resistant to implied criticism rather than open to treating it as a learning opportunity. By talking things through, those attitudes might change and we would all end up better for it.