With the parameter “always together” you can force the program to consider the loads of a load type always as one undividable load. Otherwise, ConCrete will automatically load some spans with the favourable load factor and other with the unfavourable load factor to obtain the most damaging load situation.
It can be however that the nature of the load makes it impossible to vary the load over different spans between favourable loaded and unfavourable loaded. Think e.g. at a swimming pool that can be filled with water or not. Suppose this pool is supported by continuous beam with 3 spans. The water should be introduced as a variable load with load factors γ = 1.50 and γ = 0.00. Normally, the program will include a load situation where the first and third span is loaded and the second is not. In practice, this is not a possible situation : or the water is in the pool and then, all 3 spans are loaded, or the is not in the pool and then, all 3 spans are unloaded. By indicating that the loads of the load type are always together present or not, the program will not take into account these 2 load conditions (all spans loaded and all spans unloaded).