Per Albert Breer: This year, I sent out nearly 200 requests for votes, knowing that cut-down week is a busy one, and some people won’t get back to me. This year, we received 104 ballots. All 32 teams had voters in this poll, and 30 of the 32 had multiple voters, so we have a diverse cross-section of the league. Among the voters—GMs, personnel executives, head coaches, offensive and pass-game coordinators and quarterbacks coaches—we received ballots from 20 head coaches and 21 general managers.
Going by his statement, his ballots were completed in an unofficial, voluntary method. The reported initial response is telling, namely, a slightly more than 50% cooperative rate. It can be speculated that those who actually responded did not fully complete Breer's ballots.
It may be simply a case where respondents took enough time to answer specific categories and ignored any they did not find important. It would certainly help explain some of the overall voting disparities.