I think there are two problems here, both mine. The first is that the regex is slightly wrong. I have now updated it (it was capturing when it should not have been). The second problem is that I named the fields in the Uptime struct incorrectly. They should be one, five, and fifteen, as you have them, but I named them five, ten, and fifteen. This incorrect naming was only in the section where the entire module was presented (not where it was in bits and pieces amidst explanation).
Thanks for alerting me to these. :)