Technically that is the case. As a sweeping generalisation maintenance work, e.g. DIY decorating, repairing damaged walls, replacing a few tiles etc., etc., will not be subject to IKA. For any new construction you will be liable to pay IKA. There have been discussions about this subject here and on other forums in the past
The best approach is to go to the relevant building office, with details of what you plan to do and ask how much IKA will amount to. It's calculated on time taken and level of skill required e.g. labouring is charged at a lower rate than 'specialist' work.
Simply avoiding payment is probably not worth the risk. It's not something I'd take a chance on. Someone from the building department who just happens to pass your property and sees the work in progress decides to check; you unknowingly upset a neighbour who retaliates by "enquiring" at the building office if IKA is being paid. A further risk, of which I know two cases, arose years after the work was done when the owners decided to sell. During the contract phase the current state of the properties were compared with the original plans and differences noted. The sales were held up until IKA - and, in one case, penalties - had been paid. One buyer pulled out because of the delay and the vendor had to pay around €2.5K before re-marketing the property. The other managed to hold his buyer but had to stump up nearly €4k.
Contracts may be studied quite closely. When we sold our house and apartment a couple of years ago I was required to attend the contract completion meeting at a Notary's office. Present were myself and lawyer, the buyers and their lawyer, the Notary and her assistant. The notary went through the contracts line by line, with the property plans spread across her desk, and checked and confirmed every detail with our lawyer and the buyer's lawyer. At the end, all parties present [except the Notary's assistant] signed every page of the contracts and other forms. The buyers and I also had to sign entries of contract details - numbers, date, etc., in a ledger. The whole thing took the best part of three hours.