Power feeding would suggest either oversized meals or a full size meal on a shorter than 5 day schedule. This can be done with babies, as long as they have digested their last meal before offering the next. I know most people who are raising valuable specimens up for breeding tend to feed on a more aggressive pace. Some can handle more food than others is the simple truth, though. I personally find the Munson plan to be power feeding, simply for the large meal sizes. I feed smaller meals on a 4 day, personally. I also don't even try to get any female to size by her 2nd birthday, in spite of others who will be beating me to Palmetto hets and scaleless.
As for what it can do "to" your snake, I have never seen any indication that power fed snakes were any weaker or less vigorous in any way to their more slowly fed counterparts. Like Bitsy, I have my share that were, but I find fatties to be an individual thing, and not a permanently "geared up" metabolism. A corn in the wild in an area with abundant food is going to eat it. I have asked anyone to show me a fat baby snake for 10 years, and I have yet to see one. Overfeeding an adult or subadult is a different matter, certainly. Not to argue w/you, Bitsy, just differing experiences. I'd try your fat snakes weekly on very small prey items. I have had much better luck with that.
All of this said, a key to a healthy snake IMO is activity. A snake with a huge meal in its belly constantly is going to spend much of its time sitting and digesting. Some time spent pacing the cage and stretching & exercising muscles seems paramount to good musculature and development.