Hi Testmenow,
Tickstory always uses the raw tick data to construct all the bar chart time-frames. If you are seeing different charts than for the same range you have exported, make sure you have not connected to your broker. If you connect to your broker, it will attempt a back-fill and potentially overwrite the historical chart data that you exported from Tickstory. You can prevent connection to your broker by cancelling at the login prompt.
If you are simply looking at charts then your current version of Tickstory should be fine. If you wish to back-test with the latest MT4 Build then yes, you will need to upgrade to v1.6.
Hope this helps.