Nebenkostenabrechnung, I am confused!!

Hallo zusammen, I am a university student and received few documents via whatsapp from my previous Landlord in December and does not understand on what basis, they have sent me this calculation. Fyi, I lived in a small room of 9m² and the apartment was shared among five people. When I moved out, I had asked about my deposit, and they told me after the calculations, they would give it back the following year and Now this is what I received. (I lived here from October 2022 to August 2023.) Does it look unusual and scammy? Is it common that you divide up the costs randomly without considering the apt size and other criteria’s? Thanks for the help!