With only 7 units, how hard would it be to call a general meeting (with proper notice etc) any time the committee feels there is a need to authorise some unusual spending that goes beyond being reasonably consistent with the budget approved at the AGM? By definition, unusual spending does not happen very often, whereas usual spending should be anticipated in the approved budget with varying degrees of accuracy depending on the nature of the expense.
By ‘reasonably consistent’ I mean that while some items can be predicted with great accuracy some other ordinary expected expenses can vary a bit without that being unreasonable. Eg. where I am with over 100 units and lots of trees on the common property we always have some tree surgery and the annual admin fund budget has a line for it. We might budget $6000, which is a typical amount to spend but some years we only need to spend $4000 and other years we might need to spend $8000, but we still do what needs doing when it needs doing. The budget carries over enough surplus from one year to the next to accommodate a bit of wobble in the items that are harder to predict precisely.