This is thanks to a recent report by Consumer Reports in which through independent testing of their own, they too found that there differences, if any, are negligible and should not have any drastic effects on the user, regardless of which company made the chipset in their new iPhone 6s or 6s Plus.
According to their findings, “We found no appreciable differences in battery life or temperature between the iPhones 6s models with the varying chips.” Prior to this, there was some concern when benchmarks revealed that the difference in battery life to be about 2 hours. However according to Apple and subsequent testing for real-life usage, the difference should really be about 2-3%.
Hopefully this report will reassure you about your phone, otherwise you will have 14 days within your date of purchase to return it and hopefully get the model you’re after. In the meantime the Taiwanese government isn’t too happy about the situation and have launched an investigation of their own into the matter.