Hi yousufa,

The OG is *generally* arranged in order of increasing difficulty, so you'll certainly find harder "blocks" of questions as you go deeper into any of the question pools.

There is another issue though that's worth considering. It's possible that "your approach" to handling DS questions is limited and THAT'S why you're not doing particularly well on these later blocks of DS questions. You might consider learning some new tactics and putting some extra emphasis on your organization and note-taking. DS is a big chunk of your Quant section, so if you get too many of those questions wrong, then you'll have trouble scoring in the 700+ range.

GMAT assassins aren't born, they're made,
Rich