Interesting one sentence statement in the AdminGuide, (in bold) says you can use one ITSP profile for multiple Voice Services:
Under "SIP Service Provider Features of the OBi Device"
Each ITSP configuration is grouped together as an ITSP Profile. We refer to them as ITSP Profile A, B, C[2], and D2 respectively.. The SP service account specifics on the other hand are grouped under the heading SPn Service, where n = 1, 2, 3., or 4.,. An ITSP Profile includes such parameters as ProxyServer, OutboundProxy, and DigitMap, but does not include account specific parameters. A SP Service includes account specific parameters such as AuthUserName (usually the phone number of the account), AuthPassword, CallerIDName, and X_ServProfile (which ITSP Profile to assume). If both SP Service use the same ITSP, then only one ITSP Profile needs to be configured with both SP Services referred to the same profile.