No, it's ok. I fretted over it too.

Here is the thing.
Pakistan follows British system of writing. Our English textbooks are the examples of that. However, when you move to a university, you end up reading books that are American and in universities, teacher (unless they are English language teachers) don't mind the American spellings if the grammar is correct.

CSS exams technically should also follow the British system but if you look at the English papers, these are a confused mixture. That brings me to your question.

In British language, it is "-ise"; "-ize" is American.
Globalisation, not globalization (though css papers sometimes have z)

You already mentioned the "our" thing.

There is a "c" and "s" thing too.
Defence is British, defense is American. We follow defence.

In Precis paper, we follow spelling rules of British but quotation rules of Americans. For instance, we should be writing single quote not double quote for dialogues but we do.
'You are a good person.' is British.
"You are a good person." is American.

I have to recheck this as well but usually, precis paragraphs are often american with -ize.

So I hope it helped a bit.

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