As the biases are far above one second (and also varying within each inteview), it does not make any sense to measure the page times more accurately.
If you need more accurate response times, you'll have to measure them within a page. Depending on your task, the "selection sequence" or the "assignment taks" might be a good choice. If not, one can write a bit JavaScript to measure the time.
With a bit JavaScript, if is for example possible to measure the time between the page has been loaded (with or without images/layout) and the pressing of the next button. This removes a lot of artifacts, and then it is sensible to record milliseconds.