Sequence of H&S insurance claims

Hi, I had to undergo a minor surgery and got a LOG from my company insurer, AIA. In the LOG, it is stated that Medisave should be "activated" first, which I have no issue understanding. But what I could not quite understand is that the staff told me that "NTUC" insurance needs to be next in the sequence before company insurance? My "NTUC" insurance is actually IP with rider. Is this the case that we need to always claim from our own IP before we can claim from other insurer?

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I checked with my retiring agent and was told that claim which one first not important as long as can claim. Wahaha... I am quite fine with this but because my IP comes with a co-payment while my company one is as charged but cap at a certain amount. Out of the pocket would make a difference in this case. Would be good to understand how such things work so that next time can make better decisions.