As far as I understood your community is regulated by section 24 of the HPA which tries to cover a legal loophole for those macro-developments in which there are sub-communities integrated in a master community.
One may wish to create a master community in the following situation. Assume there are four blocks of flats around a garden. Each block of flats has its own unique maintenance and covenant issues, but all blocks want to share the common garden. Each block could be a separate community with maintenance obligations, voting and other rights pertaining just to that block. Only those in the affected block would get to vote on issues relating to that block. Each sub-community has its own service fees, its Owners’ Committee, its president and its own common elements but it is also belongs to a master community with general common elements.
Each sub-community has to contribute to the expense of the master community in accordance with the allocation established for this purpose in the title, thus, there are two types of allocations some in respect of each property to its sub-communities; and others of each sub community in respect of the master community.
As I said before, everything in relation of the contribution system is established in the title aka master deed or 'declaracion de obra nueva y propiedad horizontal' of your development, bearing in mind that the amendment of its provisions requires unanimity
It is important to get a copy fully translated of the master community title of your development as well as the sub community' title of each sub community in order to find out whether the administrator is distributing the costs accordingly.