At the NCAA D3 level, we have crews of 7 with the U in the backfield. U moves to the defensive side of the line of scrimmage for scoring kicks. The wing officials check for illegal forward pass and ineligible receivers downfield. L will hold the line of scrimmage until the ball crosses, H will also hold the line and monitor any inside receivers on his side running short routes and/or blocking.
The U can see false starts and holding from his position in the backfield. I have yet to see calls in my NCAA games that are missed because U was in the backfield. As for dead-ball malarkey, U comes up after the play ends to spot the ball. B will accordion in from the opposite side, so will F and S.
MPSSAA has mechanics for both a crew of 6 with the umpire in the traditional position and a crew of 6 with the umpire in the backfield in the most recent mechanics manual. I have seen traditional mechanics on all games, so I assume that is what most current umpires are familiar with.
Alas/thankfully there is still a significant "learning curve" existing between NFHS and NCAA & NFL football, in addition to the availability of experience, and number, in/of game officials. What is necessarily "good for the goose", may not be as effective for the gander" either for players, or game officials. What is learned at one level can be developed at subsequent levels, both by players and officials. Lessons, habits, instincts learned at the current Umpire position, at youth, HS levels, not only serve Umpires well at those levels, but continue to serve, at the Umpire, as well as other positions, at higher talent levels.
"Dead ball malarky" is created and "enhanced" at lower levels, as are the skills necessary to effectively observe, and handle them effectively & responsibly. What Umpires experience behind the defensive line, is NOT, as consistently experienced and often, needs to be handled, at other positions. Subtle, often private, suggestions serve as effective means to avoid more serious infractions and interruptions.