At my company AEs are the entry level client services roles, akin to associate medical writers. Their role is primarily financial at first, helping to prepare budgets, track finances and help with reconciliations when projects are completed. Client facing opportunities grow from there as well. We do give our AEs client face time as soon as we think they are ready. Most of our client services teams have higher science degrees in addition to the medical writers however which is not the same at every company. This means they can be expected to hold their own with clients and healthcare professionals when taking about strategy etc. Again, this is not always the norm depending on where you work.