wrong values for timeZoneOffset

Hello
We are seeing erroneous timeZoneOffSet values being sent from some of the client Roku boxes. These values are outside the range of -720 to +720 (12 hours). The timeZoneOffset is calculated as follows
nowDate = CreateObject(“roDateTime”)
UTCDateHour = nowDate.getHours()
nowDate.toLocalTime()
localDateHour = nowDate.getHours()
timeZoneOffset = (UTCDateHour - localDateHour) * 60

I’ve tested the above code on my local Roku box with all different time zone settings and the above function seems to be working correctly. I was wondering if the above issue was because the client has not set the time on their Roku boxes. Does the Roku box automatically set the timezone correctly or should this be done by the client specifically? If the client does not set the time, what is the default value set on the Roku box?

Thanks