The only drawback in setting the processes value high is that the corresponding kernel settings, SEMMNS and SEMMSL need to be set higher based on the following formulas:
SEMMSL – Set to 10 plus the largest PROCESSES parameter of any Oracle database on the system.
SEMMNS – Set to the sum of the PROCESSES parameter for each Oracle database, adding the largest one twice, thenadd an additional 10 for each database.
Keep in mind preallocating the higher number of SEMMNS for instance eats up more memory but it is not very much, certainly nothing to worry about.
So it would seem that lowering the processes parameter can be done if you like but since the database is functioning it reflects that the kernel is setup correctly so you have nothing to worry about unless you add another instance and then revisit the formulas for SEMMNS and SEMMSL again