Texas does not play by Federation rules, obviously, but if you're interested, Texas Public schools have no mercy rule for 11 man. The only official rule is the NCAA rule, which allows quarters to be shortened by mutual agreement but not for a running clock. That is the OFFICIAL rule. In practice, many games involve a running clock when coaches agree. The lack of an available running clock is a big pet peeve among officials and even some coaches. A decade ago, some coaches would get HACKED if asked if we could run the clock; now most are either OK with it or just say, "no, let's play regulation" but aren't bothered by the question.
For Texas 6 man football, public or private, there is a 45 point mercy rule. It isn't a running clock rule; it is simply a game over rule. If a game has a point differential of 45 or more points at any time in the second half, the game is over. Period. Regular season or playoffs. I'd say between 40 and 60 percent of 6 man football games any given year are decided this way, however, many go deep into the 4th quarter before they end. I haven't worked 6 man football in many years but I've had games ended at the end of the first half, some with about 3 minutes to go in the game, and most points in between.
Texas has 2 main private school leagues: TAPPS and the SPC, which also has 3 or 4 Oklahoma schools. Both have a very similar mercy rule for 11 man football. At a 40 point differential at any time during the second half, the clock starts and continues to run. It doesn't revert back at all and only stops for called team time outs, injuries, and any official time out (clock going out, etc.). This rule went into effect around 2012 for TAPPS and a year or two later for the SPC and I've probably had about 8 or 10 games where the rule has come into play. Regular season and playoffs are the same.
