You can't "skip" them in the sense of not recording them. The trick is to delay start watching a program you're recording, then jump through the commercial breaks when they occur in your delayed viewing. My 622's remote has a yellow button that instantly jumps forward 30 seconds each time I click it, not sure what your 625's remote has. I find that if I wait about 20 mins. after the point when a 60-min. program starts before I restart it from the beginning then jump through all commercial breaks, by the time I'm getting close to the end of the program's schedule I'm also close to being caught up to real time in my delayed viewing. Thus for a typical 60-min. program with commercials, I'm watching the whole program content in about 40-mins. without commercials and finishing at the same time. Of course, YMMV...
ReplayTV was sued (and subsequently went out of business even though the suit was dismissed a few years later, meanwhile the legal fees were burdensome and the court case created wariness from consumers of ReplayTV's future) for having a feature that would actually skip commercials automatically in the recording process such that the result of viewing was as if the commercials were never recorded or a commercial free viewing experience. This is why TiVo's "skip ahead 30 second" feature had been a "hack/trick" to be programmed rather than out of the box ready, but I believe the new TiVo Premiere remotes are skip ahead 30 seconds ready out of the box.
I saw a document some years ago (possibly FCC re STB's for review) where Dish detailed how it could disable the skip ahead 30 second feature of its DVR's if it were ever compelled to do so. In fact, TiVo and Dish kept to referring to their feature as "Skip Ahead" 30 second feature with no mention of "commercials" to prevent antagonizing media companies even after they pledged to no longer file such "anti-commercial" skipping features. In fact in one video, Leslie would say, "Hey, that's the same time as a commercial," and she would smile her "you know what I mean" smile. That's how paranoid they were back then.
Again, the broadcasters and channel owners are impediments to innovation and killed it were they can.