That number makes more sense to me than the margin in last week's Republican survey. And as Election Advantage notes, it shows Collins with the smallest lead she's had all cycle.
In fact, if you skip the Republican result and look only at non-partisan data, it quickly becomes clear that over the last six months, poll by poll, Allen has slowly whittled down Collins' lead--from 23% back in October down to the current margin of 16%.
Allen clearly has a ways to go. But with seven months till election day, a 16 point lead certainly doesn't seem insurmountable.