Difficulty is re-calculated every 2016 blocks to give a new difficulty. That new difficulty is used from that point on and is calculated to allow a block to be solved every 600 seconds. It is a self adjusting mechanism but is only correct when it is calculated
so to be sure, if i add like 10MTH mining power ill be able to mine those 2016 blocks in no time? and as i read dificulty rising has its limits, it cant go lets say 10 times in one rise. how many % it can rise for next 2016 blocks?