Higher IMI property tax for guest house apartments

The Portuguese Government says that it will only raise IMI property tax on self-catering apartments used for tourists.

But it may eventually mean that if just one apartment in a building with many residential apartments is used as a self catering guest house or local accommodation, the entire building could be taxed at a higher level, leaving landlords out of pocket or eventually, in theory, leading to landlords passing the costs on to the other lessors in the property.
So far it means the tax will only go up for local accommodation (AL) with licences to accommodate tourists in residential apartment blocks and properties sub-divided into fractions for holiday lets.
In the Government’s proposed law project More Housing (Mais Habitação) “the vetustez* coefficient will be applied. (*One of six elements used to calculate the taxable patrimonial value of a property. An annual IMI property tax is then applied based on this value)
This means that properties used wholly or partially as local accommodation establishments have a coefficient of 1 (the maximum coefficient charged), which also takes into account the age of the properties to calculate the Taxable Patrimonial Value (VPT) of a property, from which the IMI tax is calculated.
ECO online reports that the Government’s proposal opens the door for increased IMI property taxes to be applied to ALL the fractions (apartments) of the building if there is JUST one Local Accommodation apartment let.
The Ministry of Finances denies this, stating to ECO that “for tax purposes, each autonomous fraction in the horizontal property regime is classified as a building”. Therefore, in a building with various housing fractions and one local accommodation fraction “the AL fraction alone with will be affected by the increase in IMI tax”.