B1 is Service B plus brake fluid change.
Without knowing the full history, it's difficult to know what's due.
If the car was serviced to the manufacturer's specification from new, and also never had an additional service due to mileage, then the seventh service would have been a Service A, plus ATF change (if automatic).
The eight service would have been a big one: Service B, plus brake fluid change, air filter change, and sparks plug change.
(The cabin filter is replaced at each Service B as part of the service and isn't charged for separately)
But, again, without knowing the car's full service history it's difficult to know what's due.
Regarding the DSB and ASSYST, they rely on what has been updated via the DSR and STAR (respectively), and so it's difficult to know if they are accurate. The car's ASSYST is probably more accurate - although it has been known to change half way through...