Politico has part of the story here:
Rep. Justin Amash (R-Mich.) voted against the class 30.1 percent of the time, including the five times he recorded himself as “present” rather than supporting or opposing an amendment outright.
We had the other part, here, on February 27:
In Michigan Amash's record meant that he went against his own party almost 36 percent of the time (472 votes), which makes perfect sense of the rhetoric to get more Democrats and independents into the Republican Party (without the singular "libertarian" votes, Amash voted against his own party 30 percent of the time). His election night remarks in that regard were jarring and startling in a year marked by one of the biggest partisan Republican victories nationwide in decades, but play well in a district full of Democrats and independents and union members. The clarion call of the Tea Party was not bipartisanship, but that's often the ploy of libertarians, whose small numbers keep them forever in need of allies. It's smart politics, not but it's not principled conservatism.
Amash promoted himself as consistent, principled and conservative in his campaign for the MI-3 House seat. So far, he's batting a thousand on consistent. The question is whether the voters will decide next time that consistency is, after all, merely the proverbial hobgoblin of little minds if he too often sacrifices his conservatism, and his principles, to it.