I think it is the intention that you use a single aim where possible as in the guidance below:
If a learner is following a programme of learning that involves learning across several sector subject areas, then you should record one of the learning aims in the range (Z0007848 – Z0007859). However, if the learner is undertaking learning in a single sector subject area you should use a Learning aim reference from Category A.
However, there may be occasions depending on the funding stream and circumstances where more than a single aim may be applicable (e.g. due to progression).
It’s fine to use the same Z aim multiple times. You’ll be wanting a separate ILP for each with clearly defined learning goals to show the difference between the two classes where the course title wouldn’t differentiate. My classic example though is that both oil painting and sculpture require you to use the same learning aim, it’s not our fault they’re not specific enough and the same applies to most Sector Subject Areas.
(definitely don’t worry about it for funding model 10, as there’s even fewer aims for that provision)