Hi, physical and economic allocation factors in openLCA always add up to 1 since they are calculated automatically. For causal allocation factors, it is reponsibility of the modeler - or put it differently, in causal allocation, which means manual entry of allocation factors, the modeler has the power to set each of the factors for each exchange as he or she wants. The factors entered then are not further automatically normalised (to your point 2). Personally, I think it always makes sense to have allocation factors adding up to 1.
I am pasting some pictures from a simple multioutput process, setting calculating phyisical allocation factors gets 1/3 and 2/3, setting one of the factors manually to 0.2, for CO2 output, calculates then the respective amount for CO2 as 0.2*2kg.
cogeneration multifunctional process, 2kg CO2 output
physical allocation factors, calculated
Changed factor for CO2 (i.e., applied causal allocation here)
results calculated with the manually changed factor, just for this process. Result for CO2 is 0.2*2kg