Did the insurer agree on the specific amounts or just on the principle that your claim was valid?
Also, it may also be the case that the insurance cover has an excess component which reduces the pay-out.
If that’s the case, then you should claim the balance from the owners corporation. And don’t get drawn into an argument that they are only liable for the amount insured.
If the OC has saved money in insurance premiums by including an excess, so be it. But that doesn’t mean they aren’t liable for the full amount of the damages.