Sprinkler Control Power supply requirements questions
Question 1:  The difference is because worldwide some power distribution systems are 50Hz, and some are 60Hz.  The coil in the valve reacts differently for the different supply frequencies.

Question 2: That 1000mA rating is the maximum the power supply can deliver.  The actual valve will only use what it needs to; you won't damage it in any way by using a higher capacity (current wise) supply as long as the applied voltage is proper.