Following the Supreme Court’s interpretation of excess insurance policies’ other insurance clauses in Montrose Chemical Corp. v. Superior Court (2020) 9 Cal.5th 215, this decision holds that in a case involving coverage for injuries occurring over multiple coverage periods, the insured can reach an excess policy after “vertically” exhausting any primary insurance policies for the same period, but need not exhaust all primary insurance policies “horizontally” over all time periods in which injury occurred. The decision also holds that the trial court properly allowed the insured to treat its primary insurers’ allocation of their insurance payments as between products liability and other coverages as prima facie evidence of what money was spent on which claims. Under the trial court’s ruling the excess insurers could challenge those allocations if they wished, with evidence a different allocation was proper.