If yours is “a tiny 1-bedroom unit” and others are larger, your unit entitlements are likely to be less than others. If the owners corporation does the block-wide wiring upgrade, you will pay a smaller fraction of the cost compared with others, in proportion to unit entitlements. The real cost might be rather more similar from one unit to another, regardless of size. So, you might be better off going in with everyone else than doing it separately later. And that is before even considering economies of scale.