I wish the tax code specified more rigid guidelines for how matches and true-ups worked, so that it was consistent between employers.
Before my employer was acquired, they had a good policy regarding matching and front-loading the 401k. (Not a terribly great match amount, but the way they implemented it was very fair.) If you reached the IRS contribution limit in a year, they would continue matching on every paycheck through the end of the calendar year. If for some reason you missed part of the match during the year (and on subsequent paychecks up'ed your contribution higher than the match threshold) they would do an end-of-the-year true up too.
Of course, my employer was acquired by some other company, and the policy has changed, and the continued-matching after you max it out was shut off. They said they will do a true-up, but you have to still be employed when the true-up happens in the following year. They've also made mistakes with the matching contribution (probably a result of the mergers/acquisitions and consolidating payroll processes/companies)... and there were a couple times when they've made "adjustments" to my account. Fortunately it hasn't been too much, just a hundred bucks here and there...