If you are using the
WeeWX SteelSeries Weather Gauges extension then gauge-data.txt (the data file used by the SteelSeries Weather Gauges) is only generated every archive period (for example, every five minutes). The setting you refer to in
gauges.is is how often the SteelSeries Weather Gauges code reads gauge-data.txt and refreshes the displayed gauges. This means your gauges effectively update once per archive period irrespective of the setting in gauges.js, there is nothing you can you about this with this setup.