Question about pairs combination jumps

I read what the handbook said about pairs elements, but I still don't know the answer to this.

So, two different pairs couples had a fall on their combination SBS jumps. In both cases, one partner fell, while the other partner went ahead and did the second jump. In one instance, the element was called 3S + COMBO, and in the other instance, it was called 3T + REP.

Is it something simple I'm missing? Can someone tell me the difference between a combination jump being (jump) + COMBO and (jump) + REP?

It's a good thing this subforum claims there are no stupid questions, because this feels like a stupid one to me! But it's puzzling me and I'd be glad to know the answer.

Have a read of the ISU Judging System article on Wikipedia, it summarises it pretty clearly. +rep is to do with the partiular jump being repeated as a solo jump and recieving less base value rather than being related to one person falling as far as I’m aware, but I’m not very good at explaining it so would suggest reading the article.

Elija will do.