I've had to switch from Atkins to a more PP-type program twice now. Both times appeared to be as a result of eating too much protein for my body on Atkins and I stopped short of where I really wanted to be. The first time I was also watching fat (from my pre-set notions, and a misunderstanding of the wording in PP) and I did lose the weight, but dealt with a lot of hunger and cravings. This time I dropped the protein to my minimum, but still kept my fats high, very high, in fact, and I'm losing again. No hunger this time. I do keep my carbs lower than PP, however, at 20 g total carbs per day.

I also found out that I don't lose on 30 grams NET carbs from any source any more (I used to when I was younger, but not this time), but I can still lose on 20 grams TOTAL carbs from most any source. (Usually about 12-15 grams net carbs.)

So, in a nutshell, I've switched from a traditional Atkins plan, to closer to a PP plan, twice now, in a 10 year period. Although even PP requires tweaks for me (more fat, lower carb) to work for weight loss and to control my appetite.

You can just make the switch overnight, so to speak. Just start following the PP--PPLP rules, as written, no tweaks, and see how you do.