KFW40(plus) standard multifamily house cannot be achieved

Hello everyone, I am planning the construction of a 5-family house. Since the plot is very narrow but long, the planned house will be 20.415m long but only 7.24m wide, these are the maximum possible dimensions approved by the building authority. The house will have two full floors as well as a 45° gable roof. The gables will have a southwest / northeast orientation. The exterior walls will be a two-shell masonry with a thickness of 49cm, structure 17.5 Ytong, 12cm PUR insulation 0.24 air layer and 11.5cm facing brickwork. No basement. All technical values correspond to the specifications of a KfW55 house, ground source heat pump, underfloor heating, decentralized ventilation systems, photovoltaic system including storage, etc... Nevertheless, according to the calculation by my energy consultant, the house only achieves the KfW55 standard due to the unfavorable length-to-width ratio and she has reached the limits of her expertise. Is this a calculation error or actually not possible? I am really despairing over this...

All technical values correspond to the specifications of a KfW55 house,

Nevertheless, according to the calculation by my energy consultant, the house only reaches the KfW55 standard

Typo anywhere?

Typo somewhere?

According to the thermal bridge proof, the WB factor must be 0.00 and she only achieves a maximum of 0.03, but as a layperson I can't make much of it.

So it's the envelope and not the primary energy demand or system technology? If the envelope doesn't fit, more insulation and/or better windows. It's actually not that difficult. The floor plan with only 7.24 cm is quite interesting, and then 49 cm fortress walls. It won't be cheap either with PUR insulation and clinker brick. Apartment building without a basement? Also special.

We have calculated windows with a 0.9 U-value and exterior walls with a 0.13 U-value, but according to the software, it still doesn't work. Even if you make the wall thicker and use a U-value of 0.09, the software says the values are not met. With the system technology, we have an overachievement of almost 400%.

0.13 is really already very good. There is hardly any room for improvement. How about perimeter insulation and the roof? Has she ever hypothetically calculated with a basement and adjusted the insulation thicknesses there? With the windows, however, there is still a lot of potential. 0.9 is more in the range of double glazing.