Before you jump into using any new resource, it helps to try to define your situation in as many details as possible. For example:
1) Do you have trouble finishing the Quant section on time (and do you have to guess on a bunch of questions just to finish)?
2) Do you know all of the necessary formulas and math rules?
3) Are you comfortable doing the necessary math 'by hand' during a CAT?
4) How often are you getting questions wrong because of a silly/little mistake?
It might also be that you don't need to do lots of additional practice problems so much as you might need to learn new approaches to the Quant section.
GMAT assassins aren't born, they're made,
Official Guide 2016 Question Breakdown:
GMAT Club Verified Reviews for EMPOWERgmat & Special Discount
EMPOWERgmat Podcast - A Wild Secret About The GMAT Algorithm