Specification: Support for multiple services is ambiguous

[johnbillion]

From the DID document spec in specification.md:

Valid documents SHOULD NOT contain multiple services without the FairPackageManagementRepo type unless specified by an extension to this specification. Clients which assume a single repository MUST use the first service with the matching type in the set.

This paragraph is ambiguous. The double negative means it places a constraint on services other than FairPackageManagementRepo, which I don't think is the intention. To me it reads as if one service without the FairPackageManagementRepo type is allowed, but not multiple. I'm not sure what this paragraph is intending to convey.

1. Are service types other than FairPackageManagementRepo allowed in a DID document?
2. Are multiple services of the FairPackageManagementRepo type allowed in a DID document? And does FAIR support this?