Sorry you can not buy more efiles, you can not efile more than 5. It is an IRS limit. If you need to efile more you have to buy Intuit Products for Tax Professionals https://taxpro.intuit.com and sign up with the IRS as an ERO - an Electronic Returns Originator. How to become an Authorized E-file Provider…..
http://www.irs.gov/Tax-Professionals/e-File-Providers-&-Partners/Become-an-Authorized-e-file-Provide...
Maybe they can use the Online version?
