According to David Pollack (who should know), this is due to the jerky time. See Whether this is a mistake. Liftweb TimeHelpers: 60.minutes is not equal to 1.hour .
The solution is to convert to Duration, and then compare the two values. From Period.java :
Period definition also affects the equals method. The period of 1 day is not equal to the period of 24 hours, not 1 hour, equal to 60 minutes. This is because periods are an abstract definition of a time period (for example, a day may not actually be 24 hours, it may be 23 or 25 at the border of daylight saving time). To compare the actual duration, two periods are converted as a duration using toDuration, an operation that emphasizes that the result may differ depending on the date you select.
This solution was provided by the andreak team in the above google group thread link and copied here so others can find it here.