A sales model for a rented flat assumes a higher annual depreciation than you expected. It is justified by a shorter actual useful life of the building. For your financing it is important whether this assumption has been examined concretely or is being used only as a possible tax argument.
Name the alleged deviation precisely
Note the period used in the model and the building valuation basis affected. Ask for the actual document on which the period is based. An older year of construction alone is not a complete object-specific explanation. A mere heading such as Restnutzungsdauergutachten (remaining useful life report) also does not answer which item was assessed as of which reference date.
§ 7 Absatz 4 Satz 2 EStG allows, under the conditions stated there, a deduction based on a shorter actual useful life. [ESTG7-DAUER] This article does not decide acceptance of a concrete proof and does not claim a universally required or always sufficient expert report method. The corresponding legal and tax examination remains open.
Check the object assignment
Do the address, building, relevant components and valuation date match your purchase? Which actual information on condition and measures was taken into account? A statement for a different building component or an earlier condition will not be transferred unexamined to the offered flat.
Our editorial recommendation: Have the assumptions and the limited statement of the document explained to you. Unknown circumstances remain unknown. A technically expected usage, an economic assumption and the tax treatment must be assigned correctly by expertise, rather than lumping together similarly sounding terms.
Show the financing impact with two variants
In the hypothetical case the sales calculation contains a special AfA approach that has not yet been individually confirmed for tax purposes. The household plan leaves a variant without this additional expected benefit alongside it. It does not simply apply a different high percentage, but asks the tax adviser for an appropriate substantiated basis for comparison.
The actual purchase price payable and the loan instalment do not change simply because the tax model line looks different. How an accepted deduction would affect personal tax must be calculated separately.
Conclude with a clear examination mandate
The mandate is: Does the evidence used fit the specific object and date, which current legal basis applies to its assessment and what personal tax effect may actually be applied? The answer is recorded with the document status and limitations.
The aim is neither a blanket distrust of expert reports nor the promise of additional tax savings. You should be able to recognise whether the financing calculation depends on a still open special assumption. That very dependency belongs to an independent examination before a binding decision.