This is the argument for keeping the “second half of the Omer”. It keeps this partial Aveilus completely out of Nissan.
However, it appears that the majority keep the “first half of the Omer” which includes a week of Nissan.
Argument for “first half of the Omer” is that it is effectively shorter than the “second half of the Omer” by about a week; and we do not want to fill the year up with long stretches of mourning.