Hey Guys,
well when I posted that approach, the approach was really meant to internalized the concepts
MGMAT teaches and there I felt that of course if you do the OG problems right after you learned the concept you will know how to apply it and (hopefully) get the answers correct. However, the key thing IMO is that you have to really internalize the strategies, so I suggested two things:
a) Learn the strategies and learn them early on
b) Practice them with Kaplan material or the like and then at the end come back to the official questions and make sure that you can tackle those with the strategies you have learned.
This approach is irrespective of the question difficulty level and your target score.
With respect to your concerns over the difficulty of the OG questions and other prep material compared to the real GMAT, I mean go through this forum here and you will see that some feel one way and some feel another way. To me, OG questions (just like GMATprep) is material that comes from official retired GMAT question pools and as such I feel this is as close to real as you can get.
Hope this helps