We just updated our CP and CPS documents to v1.1.
i looked at the document and found that https://letsencrypt.org/documents/ISRG-CPS-September-9-2015.pdf have incorrect page numbering. There are 115 Pages and it say 11 at all (15 of 11) for example. On legal documents this should be fixed.
Also point 1.4.1 second part with generating sub ca and oder dv-ssl certs i think does not match the purpose of tan dv-cert.
Good catch, thanks! Will fix.
I found another point 3.1.5 here it is claimed that the subject name will be unique.
But i think over time and for overlapping certificates this is not correct.