Never heard of such thing.
Trying to give you the best possible advise. If there was such a law, and there isn't, the horizontal property law is one and only, the other party should be able to provide basis for the claim.FACT.
The reglamento deals with internal rules agreed by all owners. FACT
Administrador must have copy of building blueprints and Reglamento. FACT
The agrimensor deal is nonsense, gave you good reasons why and even if such person were to redefine the portion of SQ meters that still doesn't solve your rate issue.FACT.
Believe what you want. Good luck,
Thank you for YOUR time.
Iz has left the building.