With S3's I had each had a personality of it's own.  Some operated better then others, some liked different settings.   I had everything from batch 1 S3 to S3+'s though so there is some reason for that.

If you have 500+ avg and miner looks to be mining with low hw errors or issues... I would not mess with it. Why change what is working good?

Have had several S3+ miners but only one of them was be able to run at frequency 250 with ~500Ghs stable and low HW errors.
Power consumption at the wall was about 400W

Seems a bit odd try resetting the firmware (if on latest try going a couple versions)

Tell me if it works or not