GMATPrep reinstall - how much improvement is typical?

I took GMATPrep 1 and 2 in January and got Q 48, V 38 (710) and Q 47, V 41 (720), respectively.

I re-installed GMATPrep and took GMATPrep 1 two weeks later and got Q 48, V 41 (720). So only a 10 point improvement.

Since then, I've been studying hard, and retook the 2nd test yesterday. The second time I got Q 50, V 45 (770)- a 50 point improvement. I want to know how much of this is me getting better and how much is the benefit of a handful of repeat questions. I didn't remember the answers to any of the questions.

How much did your GMATPrep scores change after re-taking after re-installing?

Here are my practice scores:
GMATPrep1 Q48, V38 710
GMATPrep2 Q47, V41 720
MGMAT1 Q40, V39 650
MGMAT2 Q43, V45 720
MGMAT3 Q43, V39 680
GMATPrep1 (reinstalled) Q48, V41 720
Real GMAT Q44, V40 690
MGMAT4 Q46, V39 700
Kaplan CD 1 Q40, V40 680
MGMAT 5 Q46, V42 720
MGMAT 6 Q49, V45 760
GMATPrep2 (reinstalled) Q50, Q45 770