5 efiles is an IRS limit per computer and email address. I think it's to prevent fraud and people filing a lot of fake returns
Read the IRS rules and restrictions for self-prepared e-file providers.
https://www.irs.gov/pub/irs-pdf/p1345.pdf
Page 31
5. Ensure that it does not transmit or accept for transmission more than five electronic returns originating from one software package or from one e-mail address;
This requirement is spelled out in detail in the ERO providers contract with the IRS.
And to prepare more than five e-files, you will need to 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...
