My understanding is that, with very few exceptions, you can only vary the payments for maintenance from shares equivalent to the unit entitlements by either an order from NCAT or a Special resolution.
In the absence of any reference to a special resolution by-law, it would seem that your previous arrangement was under “Old Spanish Customs”, as they used to say in the printing trade; that is, an informal arrangement that everyone was happy to go along with.
Assuming the lots 3 and 4 are paying for the lift because they are the only people who use it, then that should come under a special resolution or Common Property Rights By-Law.
However, as reflected in the final paragraph of the proposed by-law, it can only come into force if the benefitting owners agree to it in writing, and can only be changed with their written agreement too. (Which means if there is a previous special resolution by-law, it certainly can’t be changed on the whim of the strata manager.)
Just to complicate matters a little further, is it reasonable to assume that they owners of lots 3 and 4 are the only people to benefit from the maintenance of the lift? Surely there’s an element of the correct management of noise and safety that benefits all owners, regardless of which floor they live on.
I suspect this might be better handled by adjusting all four lots’ Unit Entitlements to reflect the additional facility provided by the lift. This may be a fairer way of sharing the costs, while making decisions about maintenance more logical and equitable too.
I also suspect that this might be beyond the ability of your strata manager. In any case, this by-law would require 75 percent of the unit entitlements voting at a general meeting to be approved. So just turn up and say no until you get a proposal that’s fair.