It’s been said that nobody over 22 should have anything to do with pop punk, either making it or listening to it. While that outlook is undoubtedly a bit harsh, especially when masterpieces by The Descendents and Green Day are thrown into the equation, it’s one that, by and large, just might be a rule of thumb.

Perhaps it’s a notion that’s started to rattle around inside the brain of The Mr. T Experience songwriter Dr. Frank. As champion of quirky pop punk, the singer/guitarist led his band up through the Berkeley scene alongside Green Day and played hooky, bubblegum pop for longer than some of his fans have been alive. On Yesterday Rules, the band’s first in four years, the good Doctor continues to branch out from his pop-punk roots and explore greener pastures more suited to his age. “London” basks in pure pop melodies nurtured on everything from Merseybeat to the lighthearted guitar jangle and sunshiny keys to produce a song that has its roots in post-college pop instead of Berkeley-styled pop punk. Frank opts for simplicity on “Jill,” an acoustic-and-voice number that, while saddled with a sickenly weepy breakup lyric, succeeds because of its raw, honest intimacy. Other tunes such as “Sorry for Freaking Out on the Phone Last Night” and “Big, Strange, Beautiful Hammer” put the band’s quirky sense of songwriting above the shimmer of tonal pop guitars; the oddball angle isn’t charming enough to carry the songs, even though they’re the songs’ main focus.

Frank hasn’t completely grown up, however, and as Yesterday Rules’ title implies still has a soft spot in his heart for plain and simple pop punk. “She’s Not a Flower” takes bouncy rhythms and a guitar’s bubblegum crunch to recall the days of carefree pop punk, and “Shining” strums on a lead guitar figure that suggests Snuff or early MTX. “Fucked Up On Life” dips the farthest into the punk formula, as the band calls on frantic guitars and sweat-it-out tempos to carry a tale of shirking responsibility that made the foundation for the ’90s output of bands like Guttermouth and The Vandals. As much experience as MTX has to cull for these songs, they’re certainly the low point of this record, suggesting that, despite his reputation, Frank would be best suited to leaving the punkier numbers to youngsters.

MTX mutated for a decade as it morphed from an art-rock act to a pop-punk architect. Yesterday Rules hints at a continued evolution for the band, one that takes it into the pastures of the pop underground. Until that process is complete, however, The Mr. T Experience will be just another aging pop-punk outfit struggling to deal with maturity.