They have hands on experience and right expertise in handling various billing softwares such as WHMCS, Blesta, Parallels Plesk Billing, HostBill, ClientExec, Parallels Customer & Business Manager and so on. Billing personnel in most cases has got good soft skills for sales as well and has proven skills in converting an enquiry to an order. Infact you get two in one, but no compromising quality on either!