Trust is something that online sellers have to build with visitors via the web interface, communications, and through sound policies. Buyers are skeptical about purchasing until they know all their costs. I personally do not purchase from online sellers that require personal information prior to their disclosure of all the costs related to the transaction.
In other words: I suspect that requiring customer information prior to revealing shipping costs may be resulting in higher cart abandonment rates.
Allowing the visitor to enter the cart, add their zip code and select their shipping method without requiring any further info will put many visitors at ease.
Perhaps this is currently possible and I am not aware of how to do it. If so, I welcome your advice. If not, it is something that is worth considering.
Regards,
Greg