[247h]

I've never tested that Delivery setting in Outlook but would agree with your assessment.

Perhaps your customer wants to use WebMail because they're behind a corporate firewall most of the time at the office and can't use Outlook there for their personal stuff, or even simply that they don't have a copy of Outlook (which isn't free) — there are many possible reasons, but in any case as they're intent on using WebMail, I suggest you mention RoundCube as it's fresh and easy to use.

I manage a very large number of personal email accounts and use Thunderbird in IMAP mode (on 2 PCs) as a quick visual tool for multiple mailboxes, then split what I collect by POP3 into two different Outlook PSTs (on 2 PCs), one of which has open archives for each year going back to 1998 — yes, 10 years of searchable emails! Not everyone hoards mail like this (pun intended)!

As for upgrading to a Reseller account, don't you presently find it limiting and/or face criticism from your customers that they cannot login to a control panel and manage their own domains?