Generally, time services adjust clocks incrementally to keep the clocks synchronized with the master clock. In cases when time is off by a large amount, like an hour in time zones that implement Daylight Savings Time, it becomes difficult and time-consuming to incrementally synchronize with the time master.
To ensure that clocks stay synchronized in that case, set nodes and the control workstation to understand Daylight Savings Time. See the script.cust sample file in the book PSSP: Installation and Migration Guide for information on setting time zones.