GU switches window manufacturer Kömmerling to Aluplast

My general contractor is changing the window manufacturer from Kömmerling to Aluplast due to delivery difficulties. In my case, instead of the planned Kömmerling 88MD window, I am now supposed to receive the Aluplast Ideal 8000 window. According to the general contractor, there is no or hardly any change in price/quality and U-values. In my internet research, I also did not find any significant differences in the descriptions of the two windows. Maybe someone can still advise me on this or contribute to the topic?!

The most noticeable difference: The Kömmerling has 3 sealing levels (middle seal) the Aluplast 2.

In my case, I am now supposed to receive the Aluplast Ideal 8000 window instead of the planned Kömmerling 88MD window. According to the main contractor, there is no/almost no change in price/quality and U-values.

In the construction specification it usually says "or equivalent" anyway when a brand is named ...

The most noticeable difference: The Kömmerling has 3 sealing levels (central seal) the Aluplast 2.

... I wouldn’t like to downgrade from CS to DS though. As far as I remember, the Ideal 8000 is also available with CS.

Thank you in advance.

In the construction performance description it usually says "or equivalent" when a brand is mentioned

Not in this case.

However, I would not like to downgrade from MD to AD. As far as I remember, the Ideal 8000 also comes in MD.

The most noticeable difference: Kömmerling has 3 sealing levels (middle seal), Aluplast has 2

According to internet research, the Ideal 8000 also has this third seal as a middle seal.

As a third seal in the window frame, the all-around middle bar on the one hand provides improved thermal insulation values, on the other hand it prevents the sash from being lifted quickly.

Exactly, the Ideal 8000 also has a central seal and thus also 3 sealing levels.

What I also consider positive is that I had trouble finding someone who can/wants to build my relatively tall windows (2.5m) in plastic. Two window manufacturers independently suggested this frame profile for it. It seems to be one of the "more stable" ones.