Yes — True Solar Time (真太阳时) correction is important, especially for large countries with one timezone (like China) or for births far from the timezone's reference meridian.
Standard clock time is a political convention. True Solar Time is astronomical — when the sun is actually at its highest point (noon) at your specific longitude. The difference can be up to an hour.
For example, someone born at 8:00 AM in western China (close to GMT+6 solar time but using GMT+8 clock time) has a True Solar Time closer to 6:00 AM — a completely different Hour Pillar.
Our system applies True Solar Time correction based on your birth location's longitude. The more accurate your birth location, the more precise your chart.