code initialization - exclude pressure

edna

hi, i´m working on a chemical conversion calculation using subroutines like posdat, fluinj and others. to vary edge conditions i want to change initial pressures. in preferences of 'thermophysical models and properties / liquids and gases / initialization' i changed a calculation from include pressure to exclude pressure and set pressure to 1013bar. after that, the result was a comletely different absolute temperature, and also partial pressures of some scalars changed. when i tried 0bar as initial pressure, i got the same results. is there any other setting to change if you choose 'code initialization exclude pressure' or have you any idea why the results change in that way?