I would go back to Retul for follow up fitting if it is free. The thing is none here knows how long or short your arms are and the same is about your body. You could be fine with either 38-40-42 handlebars, but you went to Retul to get the right fit. I think handlebar width goes along with fitting in general, so if you swap your bars, some adjustments should be/could be made for stem and your position on the bike.
Different cyclist have different experience with their bars, as you can see from the answers.

I would go back to Retul and ask them to explain you why you are given 38 bars, and what needs to be changed if you prefer wider ones. They must be experts (otherwise they wouldn't be so expensive)

Just my $0.02